diff -Naur ruby-2.0.0-p195-orig/configure ruby-2.0.0-p195/configure
--- ruby-2.0.0-p195-orig/configure	2013-05-14 12:02:28.000000000 +0000
+++ ruby-2.0.0-p195/configure	2013-05-22 06:32:23.706054700 +0000
@@ -3171,7 +3171,7 @@
     nacl_cv_os_nick=linux ;; #(
   darwin*) :
     nacl_cv_os_nick=mac ;; #(
-  cygwin*|mingw*) :
+  cygwin*|msys*|mingw*) :
     nacl_cv_os_nick=win ;; #(
   *) :
     nacl_cv_os_nick=$build_os ;;
@@ -4615,7 +4615,7 @@
 
 
 case "$host_os" in #(
-  cygwin*) :
+  cygwin*|msys*) :
 
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking for mingw32 environment" >&5
 $as_echo_n "checking for mingw32 environment... " >&6; }
@@ -5649,7 +5649,7 @@
 
 
 case "$target_os" in #(
-  cygwin*|mingw*) :
+  cygwin*|msys*|mingw*) :
     ac_cv_prog_ac_ct_OBJCOPY=":" ;; #(
   *) :
      ;;
@@ -5858,7 +5858,7 @@
 
 
 case "$target_os" in #(
-  cygwin*|mingw*) :
+  cygwin*|msys*|mingw*) :
 
     if test -n "$ac_tool_prefix"; then
   # Extract the first word of "${ac_tool_prefix}windres", so it can be a program name with args.
@@ -7514,7 +7514,7 @@
       # comments.   We  bypass  ANSI   C  mode  for  them.   Otherwise
       # extension libs cannot include those headers.
      ;; #(
-  cygwin*|darwin*|netbsd*) :
+  cygwin*|msys*|darwin*|netbsd*) :
 
       # need lgamma_r(), finite()
      ;; #(
@@ -8170,7 +8170,7 @@
 esac
 		LIBS="$LIBS" # m lib is include in root under BeOS/Haiku
 		 ;; #(
-  cygwin*) :
+  cygwin*|msys*) :
     	ac_cv_header_langinfo_h=yes
 		for ac_func in cygwin_conv_path
 do :
@@ -15822,7 +15822,7 @@
     setjmp_prefix=_
 elif test "$ac_cv_func_sigsetjmp" = yes; then
     case $target_os in #(
-  solaris*|cygwin*) :
+  solaris*|cygwin*|msys*) :
     setjmp_prefix= ;; #(
   *) :
     setjmp_prefix=sig ;;
@@ -17334,7 +17334,7 @@
   *) :
      CCDLFLAGS="$CCDLFLAGS -fno-common" ;;
 esac ;; #(
-  bsdi*|beos*|haiku*|cygwin*|mingw*|aix*|interix*) :
+  bsdi*|beos*|haiku*|cygwin*|msys*|mingw*|aix*|interix*) :
       ;; #(
   *) :
 
@@ -17521,10 +17521,10 @@
 			: ${LDSHARED='$(LD) -Bshareable -x'}
 			LDFLAGS="$LDFLAGS -L/lib -L/usr/lib -L/usr/local/lib"
 			rb_cv_dlopen=yes ;; #(
-  cygwin*|mingw*) :
+  cygwin*|msys*|mingw*) :
 
 			: ${LDSHARED='$(CC) -shared $(if $(filter-out -g -g0,$(debugflags)),,-s)'}
-			XLDFLAGS="$XLDFLAGS -Wl,--stack,0x00200000,--enable-auto-import"
+			XLDFLAGS="$XLDFLAGS -Xlinker --stack -Xlinker 0x00200000,0x00040000 -Xlinker --enable-auto-import"
 			DLDFLAGS="${DLDFLAGS} -Wl,--enable-auto-image-base,--enable-auto-import"
 			: ${LIBPATHENV=""}
 			rb_cv_dlopen=yes ;; #(
@@ -17829,7 +17829,7 @@
 
 	LOAD_RELATIVE=1
 	DLEXT=dll ;; #(
-  cygwin*|mingw*|*djgpp*) :
+  cygwin*|msys*|mingw*|*djgpp*) :
 
 	LOAD_RELATIVE=1
 	DLEXT=so ;; #(
@@ -18109,7 +18109,7 @@
 SOLIBS=
 
 case "$target_os" in #(
-  cygwin*|mingw*|beos*|haiku*|darwin*|os2-emx*) :
+  cygwin*|msys*|mingw*|beos*|haiku*|darwin*|os2-emx*) :
 
     : ${DLDLIBS=""}
      ;; #(
@@ -18334,7 +18334,7 @@
 
 	LIBRUBYARG_SHARED='-L. -L${libdir} -l$(RUBY_SO_NAME)'
 	 ;; #(
-  mingw*|cygwin*|mswin*) :
+  mingw*|cygwin*|msys*|mswin*) :
 
 	LIBRUBY_RELATIVE=yes
 	 ;; #(
@@ -18791,7 +18791,7 @@
 esac
 	CPPFLAGS="$CPPFLAGS -I/boot/home/config/include"
 	 ;; #(
-  cygwin*|mingw*) :
+  cygwin*|msys*|mingw*) :
 
 	RUBY_SO_NAME="${RUBY_SO_NAME}"'$(MAJOR)$(MINOR)$(TEENY)'
 	LIBRUBY_DLDFLAGS="${DLDFLAGS}"' -Wl,--out-implib=$(LIBRUBY)'
@@ -18803,6 +18803,13 @@
 		LIBRUBY_DLDFLAGS="${LIBRUBY_DLDFLAGS}"' $(RUBYDEF)'
 	    fi
 	     ;; #(
+  msys*) :
+
+	    if test x"$enable_shared" = xyes; then
+		LIBRUBY_SO='msys-$(RUBY_SO_NAME)'.dll
+		LIBRUBY_DLDFLAGS="${LIBRUBY_DLDFLAGS}"' $(RUBYDEF)'
+	    fi
+	     ;; #(
   mingw*) :
 
 	    RUBY_SO_NAME="${rb_cv_msvcrt}-${RUBY_SO_NAME}"
@@ -19145,7 +19152,7 @@
 
 RUBY_INSTALL_NAME="${ri_prefix}"'$(RUBY_BASE_NAME)'"${ri_suffix}"
 case "$target_os" in #(
-  cygwin*|mingw*) :
+  cygwin*|msys*|mingw*) :
 
     RUBYW_INSTALL_NAME="${ri_prefix}"'$(RUBYW_BASE_NAME)'"${ri_suffix}"
     rubyw_install_name='$(RUBYW_INSTALL_NAME)'
diff -Naur ruby-2.0.0-p195-orig/configure.in ruby-2.0.0-p195/configure.in
--- ruby-2.0.0-p195-orig/configure.in	2013-05-11 18:12:02.000000000 +0000
+++ ruby-2.0.0-p195/configure.in	2013-05-22 06:41:23.862304700 +0000
@@ -48,7 +48,7 @@
 
 AC_DEFUN([RUBY_MINGW32],
 [AS_CASE(["$host_os"],
-[cygwin*], [
+[cygwin*|msys*], [
 AC_CACHE_CHECK(for mingw32 environment, rb_cv_mingw32,
 [AC_TRY_CPP([
 #ifndef __MINGW32__
@@ -95,7 +95,7 @@
   AS_CASE(["$build_os"],
           [linux*], [nacl_cv_os_nick=linux],
           [darwin*], [nacl_cv_os_nick=mac],
-          [cygwin*|mingw*], [nacl_cv_os_nick=win],
+          [cygwin*|msys*|mingw*], [nacl_cv_os_nick=win],
           [nacl_cv_os_nick=$build_os])
 
   host="$host_cpu-chromium-$host_os-"
@@ -460,14 +460,14 @@
 ASFLAGS=$ASFLAGS
 AC_SUBST(ASFLAGS)
 
-AS_CASE(["$target_os"],[cygwin*|mingw*], [ac_cv_prog_ac_ct_OBJCOPY=":"])
+AS_CASE(["$target_os"],[cygwin*|msys*|mingw*], [ac_cv_prog_ac_ct_OBJCOPY=":"])
 
 # BSD's ports and MacPorts prefix GNU binutils with 'g'
 AC_CHECK_TOOLS(OBJDUMP, [objdump gobjdump])
 AC_CHECK_TOOLS(OBJCOPY, [objcopy gobjcopy])
 
 AS_CASE(["$target_os"],
-[cygwin*|mingw*], [
+[cygwin*|msys*|mingw*], [
     AC_CHECK_TOOL(WINDRES, windres)
     AC_CHECK_TOOL(DLLWRAP, dllwrap)
     target=`echo $target | sed "s/^$target_cpu-/-/"`
@@ -711,7 +711,7 @@
       # comments.   We  bypass  ANSI   C  mode  for  them.   Otherwise
       # extension libs cannot include those headers.
     ],
-    [cygwin*|darwin*|netbsd*], [
+    [cygwin*|msys*|darwin*|netbsd*], [
       # need lgamma_r(), finite()
     ],
     [haiku], [
@@ -887,7 +887,7 @@
 		[haiku*], [ ac_cv_func_shutdown=no])
 		LIBS="$LIBS" # m lib is include in root under BeOS/Haiku
 		],
-[cygwin*], [	ac_cv_header_langinfo_h=yes
+[cygwin*|msys*], [	ac_cv_header_langinfo_h=yes
 		AC_CHECK_FUNCS(cygwin_conv_path)
 		AC_LIBOBJ([langinfo])
 		],
@@ -1678,7 +1678,7 @@
 elif test "$ac_cv_func__setjmp" = yes; then
     setjmp_prefix=_
 elif test "$ac_cv_func_sigsetjmp" = yes; then
-    AS_CASE([$target_os],[solaris*|cygwin*],[setjmp_prefix=],[setjmp_prefix=sig])
+    AS_CASE([$target_os],[solaris*|cygwin*|msys*],[setjmp_prefix=],[setjmp_prefix=sig])
 else
     setjmp_prefix=
 fi
@@ -2248,7 +2248,7 @@
       # mkmf.rb's have_header() to fail if the desired resource happens to be
       # installed in the /usr/local tree.
       RUBY_APPEND_OPTION(CCDLFLAGS, -fno-common)],
-    [bsdi*|beos*|haiku*|cygwin*|mingw*|aix*|interix*], [ ],
+    [bsdi*|beos*|haiku*|cygwin*|msys*|mingw*|aix*|interix*], [ ],
     [
       RUBY_APPEND_OPTION(CCDLFLAGS, -fPIC)])
   else
@@ -2383,9 +2383,9 @@
 			: ${LDSHARED='$(LD) -Bshareable -x'}
 			LDFLAGS="$LDFLAGS -L/lib -L/usr/lib -L/usr/local/lib"
 			rb_cv_dlopen=yes],
-	[cygwin*|mingw*], [
+	[cygwin*|msys*|mingw*], [
 			: ${LDSHARED='$(CC) -shared $(if $(filter-out -g -g0,$(debugflags)),,-s)'}
-			XLDFLAGS="$XLDFLAGS -Wl,--stack,0x00200000,--enable-auto-import"
+			XLDFLAGS="$XLDFLAGS -Xlinker --stack -Xlinker 0x00200000,0x00040000 -Xlinker --enable-auto-import"
 			DLDFLAGS="${DLDFLAGS} -Wl,--enable-auto-image-base,--enable-auto-import"
 			: ${LIBPATHENV=""}
 			rb_cv_dlopen=yes],
@@ -2500,9 +2500,9 @@
     [os2-emx*], [
 	LOAD_RELATIVE=1
 	DLEXT=dll],
-    [cygwin*|mingw*|*djgpp*], [
+    [cygwin*|msys*|mingw*|*djgpp*], [
 	LOAD_RELATIVE=1
-	DLEXT=so],
+	DLEXT=dll],
     [
 	DLEXT=so])
 fi
@@ -2637,7 +2637,7 @@
 SOLIBS=
 
 AS_CASE(["$target_os"],
-  [cygwin*|mingw*|beos*|haiku*|darwin*|os2-emx*], [
+  [cygwin*|msys*|mingw*|beos*|haiku*|darwin*|os2-emx*], [
     : ${DLDLIBS=""}
     ],
   [
@@ -2770,7 +2770,7 @@
     [interix*], [
 	LIBRUBYARG_SHARED='-L. -L${libdir} -l$(RUBY_SO_NAME)'
 	],
-    [mingw*|cygwin*|mswin*], [
+    [mingw*|cygwin*|msys*|mswin*], [
 	LIBRUBY_RELATIVE=yes
 	])
 ], [
@@ -2965,7 +2965,7 @@
 	AS_CASE(["$target_cpu"],[powerpc*], [CFLAGS="$CFLAGS -relax_pointers"])
 	CPPFLAGS="$CPPFLAGS -I/boot/home/config/include"
 	],
-    [cygwin*|mingw*], [
+    [cygwin*|msys*|mingw*], [
 	RUBY_SO_NAME="${RUBY_SO_NAME}"'$(MAJOR)$(MINOR)$(TEENY)'
 	LIBRUBY_DLDFLAGS="${DLDFLAGS}"' -Wl,--out-implib=$(LIBRUBY)'
 	AS_CASE(["$target_os"],
@@ -2975,6 +2975,12 @@
 		LIBRUBY_DLDFLAGS="${LIBRUBY_DLDFLAGS}"' $(RUBYDEF)'
 	    fi
 	    ],
+	[msys*], [
+	    if test x"$enable_shared" = xyes; then
+		LIBRUBY_SO='msys-$(RUBY_SO_NAME)'.dll
+		LIBRUBY_DLDFLAGS="${LIBRUBY_DLDFLAGS}"' $(RUBYDEF)'
+	    fi
+	    ],
 	[mingw*], [
 	    RUBY_SO_NAME="${rb_cv_msvcrt}-${RUBY_SO_NAME}"
 	    if test x"${target_cpu}" != xi386; then
@@ -3200,7 +3206,7 @@
 
 RUBY_INSTALL_NAME="${ri_prefix}"'$(RUBY_BASE_NAME)'"${ri_suffix}"
 AS_CASE(["$target_os"],
-  [cygwin*|mingw*], [
+  [cygwin*|msys*|mingw*], [
     RUBYW_INSTALL_NAME="${ri_prefix}"'$(RUBYW_BASE_NAME)'"${ri_suffix}"
     rubyw_install_name='$(RUBYW_INSTALL_NAME)'
     ])
diff -Naur ruby-2.0.0-p195-orig/cygwin/GNUmakefile.in ruby-2.0.0-p195/cygwin/GNUmakefile.in
--- ruby-2.0.0-p195-orig/cygwin/GNUmakefile.in	2012-11-05 14:00:35.000000000 +0000
+++ ruby-2.0.0-p195/cygwin/GNUmakefile.in	2013-05-22 06:32:23.752929700 +0000
@@ -6,6 +6,8 @@
 
 ifeq (@target_os@,cygwin)
   DLL_BASE_NAME := $(LIBRUBY_SO:.dll=)
+else ifeq (@target_os@,msys)
+  DLL_BASE_NAME := $(LIBRUBY_SO:.dll=)
 else
   DLL_BASE_NAME := $(RUBY_SO_NAME)
   DLLWRAP += -mno-cygwin
@@ -103,6 +105,12 @@
 	$(ECHO) generating $@
 	$(Q) @DLLWRAP@ -s --def=$(RUBYDEF) -o $@
 endif
+
+ifeq (@target_os@,msys)
+msys2-$(RUBY_INSTALL_NAME)$(MAJOR)$(MINOR)$(TEENY).dll: $(LIBRUBY_A) $(RUBYDEF)
+	$(ECHO) generating $@
+	$(Q) @DLLWRAP@ -s --def=$(RUBYDEF) -o $@
+endif
 
 clean-local::
 	@$(RM) $(RUBY_EXP) $(RCFILES:.rc=.res.@OBJEXT@)
diff -Naur ruby-2.0.0-p195-orig/ext/dl/win32/extconf.rb ruby-2.0.0-p195/ext/dl/win32/extconf.rb
--- ruby-2.0.0-p195-orig/ext/dl/win32/extconf.rb	2012-12-11 03:02:04.000000000 +0000
+++ ruby-2.0.0-p195/ext/dl/win32/extconf.rb	2013-05-22 06:32:23.768554700 +0000
@@ -1,3 +1,3 @@
-if compiled?('dl') and !compiled?('fiddle') and $mswin||$bccwin||$mingw||$cygwin
+if compiled?('dl') and !compiled?('fiddle') and $mswin||$bccwin||$mingw||$cygwin||$msys
   create_makefile('win32')
 end
diff -Naur ruby-2.0.0-p195-orig/ext/etc/extconf.rb ruby-2.0.0-p195/ext/etc/extconf.rb
--- ruby-2.0.0-p195-orig/ext/etc/extconf.rb	2010-09-15 23:27:48.000000000 +0000
+++ ruby-2.0.0-p195/ext/etc/extconf.rb	2013-05-22 06:32:23.768554700 +0000
@@ -22,7 +22,7 @@
     $defs.push("-DPW_AGE2VAL="+f)
   end
   have_struct_member('struct passwd', 'pw_class', 'pwd.h')
-  have_struct_member('struct passwd', 'pw_comment', 'pwd.h') unless /cygwin/ === RUBY_PLATFORM
+  have_struct_member('struct passwd', 'pw_comment', 'pwd.h') unless /cygwin|msys/ === RUBY_PLATFORM
   have_struct_member('struct passwd', 'pw_expire', 'pwd.h')
   have_struct_member('struct passwd', 'pw_passwd', 'pwd.h')
   have_struct_member('struct group', 'gr_passwd', 'grp.h')
diff -Naur ruby-2.0.0-p195-orig/ext/fiddle/win32/extconf.rb ruby-2.0.0-p195/ext/fiddle/win32/extconf.rb
--- ruby-2.0.0-p195-orig/ext/fiddle/win32/extconf.rb	2012-12-10 09:03:17.000000000 +0000
+++ ruby-2.0.0-p195/ext/fiddle/win32/extconf.rb	2013-05-22 06:32:23.768554700 +0000
@@ -1,3 +1,3 @@
-if compiled?('fiddle') and $mswin||$mingw||$cygwin
+if compiled?('fiddle') and $mswin||$mingw||$cygwin||$msys
   create_makefile('win32')
 end
diff -Naur ruby-2.0.0-p195-orig/ext/readline/extconf.rb ruby-2.0.0-p195/ext/readline/extconf.rb
--- ruby-2.0.0-p195-orig/ext/readline/extconf.rb	2013-02-01 05:37:29.000000000 +0000
+++ ruby-2.0.0-p195/ext/readline/extconf.rb	2013-05-22 06:32:23.784179700 +0000
@@ -25,7 +25,7 @@
 dir_config("readline")
 enable_libedit = enable_config("libedit")
 
-have_library("user32", nil) if /cygwin/ === RUBY_PLATFORM
+have_library("user32", nil) if /cygwin|msys/ === RUBY_PLATFORM
 have_library("ncurses", "tgetnum") ||
   have_library("termcap", "tgetnum") ||
   have_library("curses", "tgetnum")
diff -Naur ruby-2.0.0-p195-orig/ext/socket/extconf.rb ruby-2.0.0-p195/ext/socket/extconf.rb
--- ruby-2.0.0-p195-orig/ext/socket/extconf.rb	2013-01-26 02:31:40.000000000 +0000
+++ ruby-2.0.0-p195/ext/socket/extconf.rb	2013-05-22 06:32:23.784179700 +0000
@@ -6,7 +6,7 @@
 when /(ms|bcc)win(32|64)|mingw/
   test_func = "WSACleanup"
   have_library("ws2_32", "WSACleanup")
-when /cygwin/
+when /cygwin|msys/
   test_func = "socket"
 when /beos/
   test_func = "socket"
@@ -35,7 +35,7 @@
 end
 
 ipv6 = false
-default_ipv6 = /cygwin|beos|haiku/ !~ RUBY_PLATFORM
+default_ipv6 = /cygwin|msys|beos|haiku/ !~ RUBY_PLATFORM
 if enable_config("ipv6", default_ipv6)
   if checking_for("ipv6") {try_link(<<EOF)}
 #include <sys/types.h>
@@ -110,7 +110,7 @@
   $defs[-1] = "-DHAVE_SA_LEN "
 end
 
-have_header("netinet/tcp.h") if /cygwin/ !~ RUBY_PLATFORM # for cygwin 1.1.5
+have_header("netinet/tcp.h") if /cygwin|msys/ !~ RUBY_PLATFORM # for cygwin 1.1.5
 have_header("netinet/udp.h")
 
 if !have_macro("IPPROTO_IPV6", headers) && have_const("IPPROTO_IPV6", headers)
diff -Naur ruby-2.0.0-p195-orig/ext/tk/extconf.rb ruby-2.0.0-p195/ext/tk/extconf.rb
--- ruby-2.0.0-p195-orig/ext/tk/extconf.rb	2013-01-10 07:47:20.000000000 +0000
+++ ruby-2.0.0-p195/ext/tk/extconf.rb	2013-05-22 06:29:49.268554700 +0000
@@ -106,7 +106,7 @@
 # fuctions
 ##############################################################
 def is_win32?
-  /mswin|mingw|cygwin|bccwin/ =~ RUBY_PLATFORM
+  /mswin|mingw|bccwin/ =~ RUBY_PLATFORM
 end
 
 def is_macosx?
@@ -602,7 +602,7 @@
         #puts "check #{file} #{$1} #{tclfunc} #{tcldir}"
         #find_library($1, tclfunc, tcldir)
         if (tclconf && tclconf["TCL_SHARED_BUILD"] == "0") ||
-            (ext != CONFIG['DLEXT'] && ext == CONFIG['LIBEXT']) || ext == "a"
+            (!tclconf && ((ext != CONFIG['DLEXT'] && ext == CONFIG['LIBEXT']) || ext == "a"))
           # static link
           tcllibs = $libs + " -DSTATIC_BUILD " + file.quote
 
@@ -645,7 +645,7 @@
         #puts "check #{file} #{$1} #{tkfunc} #{tkdir}"
         # find_library($1, tkfunc, tkdir)
         if (tkconf && tkconf["TCL_SHARED_BUILD"] == "0") ||
-            (ext != CONFIG['DLEXT'] && ext == CONFIG['LIBEXT']) || ext == "a"
+            (!tkconf && ((ext != CONFIG['DLEXT'] && ext == CONFIG['LIBEXT']) || ext == "a"))
           # static link
           tklibs = " -DSTATIC_BUILD " + file.quote
 
@@ -1784,7 +1784,6 @@
   print("\n") # progress
 end
 $CPPFLAGS ||= ""
-$CPPFLAGS += ' -D_WIN32' if /cygwin/ =~ RUBY_PLATFORM
 
 # Does ruby have nativethread ?
 TkLib_Config["ruby_with_thread"] =
diff -Naur ruby-2.0.0-p195-orig/ext/tk/lib/tk.rb ruby-2.0.0-p195/ext/tk/lib/tk.rb
--- ruby-2.0.0-p195-orig/ext/tk/lib/tk.rb	2011-05-26 23:36:33.000000000 +0000
+++ ruby-2.0.0-p195/ext/tk/lib/tk.rb	2013-05-22 06:32:23.815429700 +0000
@@ -1180,7 +1180,7 @@
       if WITH_RUBY_VM ### check Ruby 1.9 !!!!!!!
         # *** NEED TO FIX ***
         case RUBY_PLATFORM
-        when /cygwin/
+        when /cygwin|msys/
           RUN_EVENTLOOP_ON_MAIN_THREAD = true
         when /darwin/ # MacOS X
 =begin
diff -Naur ruby-2.0.0-p195-orig/ext/tk/old-extconf.rb ruby-2.0.0-p195/ext/tk/old-extconf.rb
--- ruby-2.0.0-p195-orig/ext/tk/old-extconf.rb	2009-07-13 02:43:44.000000000 +0000
+++ ruby-2.0.0-p195/ext/tk/old-extconf.rb	2013-05-22 06:32:23.815429700 +0000
@@ -2,7 +2,7 @@
 
 require 'mkmf'
 
-is_win32 = (/mswin|mingw|cygwin|bccwin/ =~ RUBY_PLATFORM)
+is_win32 = (/mswin|mingw|cygwin|msys|bccwin/ =~ RUBY_PLATFORM)
 #is_macosx = (/darwin/ =~ RUBY_PLATFORM)
 
 have_func("ruby_native_thread_p", "ruby.h")
@@ -405,7 +405,7 @@
            find_tcl(tcllib, stubs, tclver, *tcl_ldir_list) &&
            find_tk(tklib, stubs, tkver, *tk_ldir_list) ) )
   $CPPFLAGS += ' -DUSE_TCL_STUBS -DUSE_TK_STUBS' if stubs
-  $CPPFLAGS += ' -D_WIN32' if /cygwin/ =~ RUBY_PLATFORM
+  $CPPFLAGS += ' -D_WIN32' if /cygwin|msys/ =~ RUBY_PLATFORM
 
   if tcltk_framework
     if tcl_framework_header
diff -Naur ruby-2.0.0-p195-orig/ext/tk/stubs.c ruby-2.0.0-p195/ext/tk/stubs.c
--- ruby-2.0.0-p195-orig/ext/tk/stubs.c	2012-07-09 15:52:49.000000000 +0000
+++ ruby-2.0.0-p195/ext/tk/stubs.c	2013-05-22 06:29:49.284179700 +0000
@@ -71,7 +71,7 @@
 
 #if defined USE_TCL_STUBS && defined USE_TK_STUBS
 
-#if defined _WIN32 || defined __CYGWIN__
+#if defined _WIN32
 #  ifdef HAVE_RUBY_RUBY_H
 #    include "ruby/util.h"
 #  else
@@ -100,6 +100,10 @@
 #  undef DLEXT
 #  define DLEXT ".dylib"
 # endif
+# if defined(__CYGWIN__)
+#  undef DLEXT
+#  define DLEXT ".dll"
+# endif
 #endif
 
 static DL_HANDLE tcl_dll = (DL_HANDLE)0;
diff -Naur ruby-2.0.0-p195-orig/ext/win32ole/extconf.rb ruby-2.0.0-p195/ext/win32ole/extconf.rb
--- ruby-2.0.0-p195-orig/ext/win32ole/extconf.rb	2013-01-18 02:23:37.000000000 +0000
+++ ruby-2.0.0-p195/ext/win32ole/extconf.rb	2013-05-22 06:32:23.831054700 +0000
@@ -5,7 +5,7 @@
 require 'mkmf'
 
 case RUBY_PLATFORM
-when /cygwin/
+when /cygwin|msys/
   inc = nil
   lib = '/usr/lib/w32api'
 end
diff -Naur ruby-2.0.0-p195-orig/file.c ruby-2.0.0-p195/file.c
--- ruby-2.0.0-p195-orig/file.c	2013-04-24 15:43:05.000000000 +0000
+++ ruby-2.0.0-p195/file.c	2013-05-22 06:31:57.424804700 +0000
@@ -4181,7 +4181,6 @@
 
 #ifdef __CYGWIN__
 #include <winerror.h>
-extern unsigned long __attribute__((stdcall)) GetLastError(void);
 #endif
 
 static VALUE
diff -Naur ruby-2.0.0-p195-orig/lib/fileutils.rb ruby-2.0.0-p195/lib/fileutils.rb
--- ruby-2.0.0-p195-orig/lib/fileutils.rb	2013-04-11 17:00:49.000000000 +0000
+++ ruby-2.0.0-p195/lib/fileutils.rb	2013-05-22 06:32:23.831054700 +0000
@@ -539,7 +539,7 @@
   OPT_TABLE['move'] = [:force, :noop, :verbose, :secure]
 
   def rename_cannot_overwrite_file?   #:nodoc:
-    /cygwin|mswin|mingw|bccwin|emx/ =~ RUBY_PLATFORM
+    /cygwin|msys|mswin|mingw|bccwin|emx/ =~ RUBY_PLATFORM
   end
   private_module_function :rename_cannot_overwrite_file?
 
diff -Naur ruby-2.0.0-p195-orig/lib/mkmf.rb ruby-2.0.0-p195/lib/mkmf.rb
--- ruby-2.0.0-p195-orig/lib/mkmf.rb	2013-04-14 14:55:53.000000000 +0000
+++ ruby-2.0.0-p195/lib/mkmf.rb	2013-05-22 06:32:23.831054700 +0000
@@ -121,6 +121,7 @@
   $bccwin = /bccwin/ =~ RUBY_PLATFORM
   $mingw = /mingw/ =~ RUBY_PLATFORM
   $cygwin = /cygwin/ =~ RUBY_PLATFORM
+  $cygwin = /msys/ =~ RUBY_PLATFORM
   $netbsd = /netbsd/ =~ RUBY_PLATFORM
   $os2 = /os2/ =~ RUBY_PLATFORM
   $beos = /beos/ =~ RUBY_PLATFORM
@@ -1761,6 +1762,12 @@
           IO.popen(["cygpath", "-u", path], &:read).chomp
         end
       end
+    when 'msys'
+      if CONFIG['target_os'] != 'msys'
+        def mkintpath(path)
+          IO.popen(["cygpath", "-u", path], &:read).chomp
+        end
+      end
     end
   end
   unless method_defined?(:mkintpath)
@@ -1777,7 +1784,7 @@
 SHELL = /bin/sh
 
 # V=0 quiet, V=1 verbose.  other values don't work.
-V = 0
+V = 1
 Q1 = $(V:1=)
 Q = $(Q1:0=@)
 ECHO1 = $(V:1=@#{CONFIG['NULLCMD']})
diff -Naur ruby-2.0.0-p195-orig/lib/rake/application.rb ruby-2.0.0-p195/lib/rake/application.rb
--- ruby-2.0.0-p195-orig/lib/rake/application.rb	2012-11-29 19:16:46.000000000 +0000
+++ ruby-2.0.0-p195/lib/rake/application.rb	2013-05-22 06:32:23.846679700 +0000
@@ -291,7 +291,7 @@
     end
 
     def unix?
-      RbConfig::CONFIG['host_os'] =~ /(aix|darwin|linux|(net|free|open)bsd|cygwin|solaris|irix|hpux)/i
+      RbConfig::CONFIG['host_os'] =~ /(aix|darwin|linux|(net|free|open)bsd|cygwin|msys|solaris|irix|hpux)/i
     end
 
     def windows?
diff -Naur ruby-2.0.0-p195-orig/lib/resolv.rb ruby-2.0.0-p195/lib/resolv.rb
--- ruby-2.0.0-p195-orig/lib/resolv.rb	2011-10-31 12:03:49.000000000 +0000
+++ ruby-2.0.0-p195/lib/resolv.rb	2013-05-22 06:32:23.846679700 +0000
@@ -923,7 +923,7 @@
         if File.exist? filename
           config_hash = Config.parse_resolv_conf(filename)
         else
-          if /mswin|cygwin|mingw|bccwin/ =~ RUBY_PLATFORM
+          if /mswin|cygwin|msys|mingw|bccwin/ =~ RUBY_PLATFORM
             require 'win32/resolv'
             search, nameserver = Win32::Resolv.get_resolv_info
             config_hash = {}
diff -Naur ruby-2.0.0-p195-orig/lib/rubygems/platform.rb ruby-2.0.0-p195/lib/rubygems/platform.rb
--- ruby-2.0.0-p195-orig/lib/rubygems/platform.rb	2012-11-29 06:52:18.000000000 +0000
+++ ruby-2.0.0-p195/lib/rubygems/platform.rb	2013-05-22 06:32:23.846679700 +0000
@@ -68,6 +68,7 @@
       @os, @version = case os
                       when /aix(\d+)?/ then             [ 'aix',       $1  ]
                       when /cygwin/ then                [ 'cygwin',    nil ]
+                      when /msys/ then                  [ 'msys',      nil ]
                       when /darwin(\d+)?/ then          [ 'darwin',    $1  ]
                       when /^macruby$/ then             [ 'macruby',   nil ]
                       when /freebsd(\d+)?/ then         [ 'freebsd',   $1  ]
diff -Naur ruby-2.0.0-p195-orig/lib/rubygems.rb ruby-2.0.0-p195/lib/rubygems.rb
--- ruby-2.0.0-p195-orig/lib/rubygems.rb	2013-03-17 15:07:00.000000000 +0000
+++ ruby-2.0.0-p195/lib/rubygems.rb	2013-05-22 06:32:23.862304700 +0000
@@ -120,6 +120,7 @@
   WIN_PATTERNS = [
     /bccwin/i,
     /cygwin/i,
+    /msys/i,
     /djgpp/i,
     /mingw/i,
     /mswin/i,
diff -Naur ruby-2.0.0-p195-orig/test/dbm/test_dbm.rb ruby-2.0.0-p195/test/dbm/test_dbm.rb
--- ruby-2.0.0-p195-orig/test/dbm/test_dbm.rb	2012-02-19 14:44:36.000000000 +0000
+++ ruby-2.0.0-p195/test/dbm/test_dbm.rb	2013-05-22 06:32:23.862304700 +0000
@@ -21,6 +21,13 @@
         raise 'cannot get system name' if uname.call(utsname) == -1
 
         utsname.unpack('A20' * 5)[0]
+      when 'msys'
+        require 'Win32API'
+        uname = Win32API.new('msys-2.0', 'uname', 'P', 'I')
+        utsname = ' ' * 100
+        raise 'cannot get system name' if uname.call(utsname) == -1
+
+        utsname.unpack('A21' * 5)[0]
       else
         RbConfig::CONFIG['target_os']
       end
diff -Naur ruby-2.0.0-p195-orig/test/dl/test_base.rb ruby-2.0.0-p195/test/dl/test_base.rb
--- ruby-2.0.0-p195-orig/test/dl/test_base.rb	2012-11-29 02:58:34.000000000 +0000
+++ ruby-2.0.0-p195/test/dl/test_base.rb	2013-05-22 06:32:23.877929700 +0000
@@ -9,6 +9,9 @@
 when /cygwin/
   libc_so = "cygwin1.dll"
   libm_so = "cygwin1.dll"
+when /msys/
+  libc_so = "msys-2.0.dll"
+  libm_so = "msys-2.0.dll"
 when /x86_64-linux/
   libc_so = "/lib64/libc.so.6"
   libm_so = "/lib64/libm.so.6"
diff -Naur ruby-2.0.0-p195-orig/test/fiddle/helper.rb ruby-2.0.0-p195/test/fiddle/helper.rb
--- ruby-2.0.0-p195-orig/test/fiddle/helper.rb	2012-11-27 19:54:50.000000000 +0000
+++ ruby-2.0.0-p195/test/fiddle/helper.rb	2013-05-22 06:32:23.877929700 +0000
@@ -10,6 +10,9 @@
 when /cygwin/
   libc_so = "cygwin1.dll"
   libm_so = "cygwin1.dll"
+when /msys/
+  libc_so = "msys-2.0.dll"
+  libm_so = "msys-2.0.dll"
 when /x86_64-linux/
   libc_so = "/lib64/libc.so.6"
   libm_so = "/lib64/libm.so.6"
diff -Naur ruby-2.0.0-p195-orig/test/gdbm/test_gdbm.rb ruby-2.0.0-p195/test/gdbm/test_gdbm.rb
--- ruby-2.0.0-p195-orig/test/gdbm/test_gdbm.rb	2012-07-25 06:49:35.000000000 +0000
+++ ruby-2.0.0-p195/test/gdbm/test_gdbm.rb	2013-05-22 06:32:23.877929700 +0000
@@ -21,6 +21,13 @@
         raise 'cannot get system name' if uname.call(utsname) == -1
 
         utsname.unpack('A20' * 5)[0]
+      when 'msys'
+        require 'Win32API'
+        uname = Win32API.new('msys-2.0', 'uname', 'P', 'I')
+        utsname = ' ' * 100
+        raise 'cannot get system name' if uname.call(utsname) == -1
+
+        utsname.unpack('A21' * 5)[0]
       else
         RbConfig::CONFIG['target_os']
       end
diff -Naur ruby-2.0.0-p195-orig/test/ruby/test_argf.rb ruby-2.0.0-p195/test/ruby/test_argf.rb
--- ruby-2.0.0-p195-orig/test/ruby/test_argf.rb	2012-12-24 00:45:26.000000000 +0000
+++ ruby-2.0.0-p195/test/ruby/test_argf.rb	2013-05-22 06:32:23.877929700 +0000
@@ -54,7 +54,7 @@
   end
 
   def no_safe_rename
-    /cygwin|mswin|mingw|bccwin/ =~ RUBY_PLATFORM
+    /cygwin|msys|mswin|mingw|bccwin/ =~ RUBY_PLATFORM
   end
 
   def assert_src_expected(line, src, args = nil)
diff -Naur ruby-2.0.0-p195-orig/test/ruby/test_file_exhaustive.rb ruby-2.0.0-p195/test/ruby/test_file_exhaustive.rb
--- ruby-2.0.0-p195-orig/test/ruby/test_file_exhaustive.rb	2013-04-11 16:47:45.000000000 +0000
+++ ruby-2.0.0-p195/test/ruby/test_file_exhaustive.rb	2013-05-22 06:32:23.909179700 +0000
@@ -128,7 +128,7 @@
         assert_nothing_raised { File.stat(File.basename(prefix)) }
       end
     end
-  end if /mswin|mingw|cygwin/ =~ RUBY_PLATFORM
+  end if /mswin|mingw|cygwin|msys/ =~ RUBY_PLATFORM
 
   def test_directory_p
     assert(File.directory?(@dir))
@@ -176,7 +176,7 @@
   end
 
   def test_readable_p
-    return if /cygwin|mswin|bccwin|mingw|emx/ =~ RUBY_PLATFORM
+    return if /cygwin|msys|mswin|bccwin|mingw|emx/ =~ RUBY_PLATFORM
     return if Process.euid == 0
     File.chmod(0200, @file)
     assert(!(File.readable?(@file)))
@@ -186,7 +186,7 @@
   end
 
   def test_readable_real_p
-    return if /cygwin|mswin|bccwin|mingw|emx/ =~ RUBY_PLATFORM
+    return if /cygwin|msys|mswin|bccwin|mingw|emx/ =~ RUBY_PLATFORM
     return if Process.euid == 0
     File.chmod(0200, @file)
     assert(!(File.readable_real?(@file)))
@@ -196,7 +196,7 @@
   end
 
   def test_world_readable_p
-    return if /cygwin|mswin|bccwin|mingw|emx/ =~ RUBY_PLATFORM
+    return if /cygwin|msys|mswin|bccwin|mingw|emx/ =~ RUBY_PLATFORM
     File.chmod(0006, @file)
     assert(File.world_readable?(@file))
     File.chmod(0060, @file)
@@ -207,7 +207,7 @@
   end
 
   def test_writable_p
-    return if /cygwin|mswin|bccwin|mingw|emx/ =~ RUBY_PLATFORM
+    return if /cygwin|msys|mswin|bccwin|mingw|emx/ =~ RUBY_PLATFORM
     return if Process.euid == 0
     File.chmod(0400, @file)
     assert(!(File.writable?(@file)))
@@ -217,7 +217,7 @@
   end
 
   def test_writable_real_p
-    return if /cygwin|mswin|bccwin|mingw|emx/ =~ RUBY_PLATFORM
+    return if /cygwin|msys|mswin|bccwin|mingw|emx/ =~ RUBY_PLATFORM
     return if Process.euid == 0
     File.chmod(0400, @file)
     assert(!(File.writable_real?(@file)))
@@ -227,7 +227,7 @@
   end
 
   def test_world_writable_p
-    return if /cygwin|mswin|bccwin|mingw|emx/ =~ RUBY_PLATFORM
+    return if /cygwin|msys|mswin|bccwin|mingw|emx/ =~ RUBY_PLATFORM
     File.chmod(0006, @file)
     assert(File.world_writable?(@file))
     File.chmod(0060, @file)
@@ -238,7 +238,7 @@
   end
 
   def test_executable_p
-    return if /cygwin|mswin|bccwin|mingw|emx/ =~ RUBY_PLATFORM
+    return if /cygwin|msys|mswin|bccwin|mingw|emx/ =~ RUBY_PLATFORM
     File.chmod(0100, @file)
     assert(File.executable?(@file))
     File.chmod(0600, @file)
@@ -247,7 +247,7 @@
   end
 
   def test_executable_real_p
-    return if /cygwin|mswin|bccwin|mingw|emx/ =~ RUBY_PLATFORM
+    return if /cygwin|msys|mswin|bccwin|mingw|emx/ =~ RUBY_PLATFORM
     File.chmod(0100, @file)
     assert(File.executable_real?(@file))
     File.chmod(0600, @file)
@@ -276,7 +276,7 @@
   end
 
   def test_owned_p ## xxx
-    return if /cygwin|mswin|bccwin|mingw|emx/ =~ RUBY_PLATFORM
+    return if /cygwin|msys|mswin|bccwin|mingw|emx/ =~ RUBY_PLATFORM
     assert(File.owned?(@file))
     assert(File.grpowned?(@file))
   end
@@ -337,7 +337,7 @@
   end
 
   def test_chmod
-    return if /cygwin|mswin|bccwin|mingw|emx/ =~ RUBY_PLATFORM
+    return if /cygwin|msys|mswin|bccwin|mingw|emx/ =~ RUBY_PLATFORM
     assert_equal(1, File.chmod(0444, @file))
     assert_equal(0444, File.stat(@file).mode % 01000)
     assert_equal(0, File.open(@file) {|f| f.chmod(0222)})
@@ -347,7 +347,7 @@
   end
 
   def test_lchmod
-    return if /cygwin|mswin|bccwin|mingw|emx/ =~ RUBY_PLATFORM
+    return if /cygwin|msys|mswin|bccwin|mingw|emx/ =~ RUBY_PLATFORM
     assert_equal(1, File.lchmod(0444, @file))
     assert_equal(0444, File.stat(@file).mode % 01000)
     File.lchmod(0600, @file)
@@ -406,7 +406,7 @@
   end
 
   def test_umask
-    return if /cygwin|mswin|bccwin|mingw|emx/ =~ RUBY_PLATFORM
+    return if /cygwin|msys|mswin|bccwin|mingw|emx/ =~ RUBY_PLATFORM
     prev = File.umask(0777)
     assert_equal(0777, File.umask)
     open(@nofile, "w") { }
@@ -418,7 +418,7 @@
 
   def test_expand_path
     assert_equal(@file, File.expand_path(File.basename(@file), File.dirname(@file)))
-    if /cygwin|mingw|mswin|bccwin/ =~ RUBY_PLATFORM
+    if /cygwin|msys|mingw|mswin|bccwin/ =~ RUBY_PLATFORM
       assert_equal(@file, File.expand_path(@file + " "))
       assert_equal(@file, File.expand_path(@file + "."))
       assert_equal(@file, File.expand_path(@file + "::$DATA"))
@@ -715,7 +715,7 @@
     assert_equal("foo", File.basename("foo", ".ext"))
     assert_equal("foo", File.basename("foo.ext", ".ext"))
     assert_equal("foo", File.basename("foo.ext", ".*"))
-    if /cygwin|mingw|mswin|bccwin/ =~ RUBY_PLATFORM
+    if /cygwin|msys|mingw|mswin|bccwin/ =~ RUBY_PLATFORM
       basename = File.basename(@file)
       assert_equal(basename, File.basename(@file + " "))
       assert_equal(basename, File.basename(@file + "."))
@@ -764,7 +764,7 @@
     infixes = ["", " ", "."]
     infixes2 = infixes + [".ext "]
     appendixes = [""]
-    if /cygwin|mingw|mswin|bccwin/ =~ RUBY_PLATFORM
+    if /cygwin|msys|mingw|mswin|bccwin/ =~ RUBY_PLATFORM
       appendixes << " " << "." << "::$DATA" << "::$DATA.bar"
     end
     prefixes.each do |prefix|
@@ -898,7 +898,7 @@
     assert_equal(true, test(?=, @file, @file))
     assert_equal(false, test(?>, @file, @file))
     assert_equal(false, test(?<, @file, @file))
-    unless /cygwin/ =~ RUBY_PLATFORM
+    unless /cygwin|msys/ =~ RUBY_PLATFORM
       assert_equal(false, test(?=, @file, @file + "2"))
       assert_equal(false, test(?>, @file, @file + "2"))
       assert_equal(true, test(?>, @file + "2", @file))
@@ -992,7 +992,7 @@
   end
 
   def test_stat_readable_p
-    return if /cygwin|mswin|bccwin|mingw|emx/ =~ RUBY_PLATFORM
+    return if /cygwin|msys|mswin|bccwin|mingw|emx/ =~ RUBY_PLATFORM
     return if Process.euid == 0
     File.chmod(0200, @file)
     assert(!(File::Stat.new(@file).readable?))
@@ -1001,7 +1001,7 @@
   end
 
   def test_stat_readable_real_p
-    return if /cygwin|mswin|bccwin|mingw|emx/ =~ RUBY_PLATFORM
+    return if /cygwin|msys|mswin|bccwin|mingw|emx/ =~ RUBY_PLATFORM
     return if Process.euid == 0
     File.chmod(0200, @file)
     assert(!(File::Stat.new(@file).readable_real?))
@@ -1010,7 +1010,7 @@
   end
 
   def test_stat_world_readable_p
-    return if /cygwin|mswin|bccwin|mingw|emx/ =~ RUBY_PLATFORM
+    return if /cygwin|msys|mswin|bccwin|mingw|emx/ =~ RUBY_PLATFORM
     File.chmod(0006, @file)
     assert(File::Stat.new(@file).world_readable?)
     File.chmod(0060, @file)
@@ -1020,7 +1020,7 @@
   end
 
   def test_stat_writable_p
-    return if /cygwin|mswin|bccwin|mingw|emx/ =~ RUBY_PLATFORM
+    return if /cygwin|msys|mswin|bccwin|mingw|emx/ =~ RUBY_PLATFORM
     return if Process.euid == 0
     File.chmod(0400, @file)
     assert(!(File::Stat.new(@file).writable?))
@@ -1029,7 +1029,7 @@
   end
 
   def test_stat_writable_real_p
-    return if /cygwin|mswin|bccwin|mingw|emx/ =~ RUBY_PLATFORM
+    return if /cygwin|msys|mswin|bccwin|mingw|emx/ =~ RUBY_PLATFORM
     return if Process.euid == 0
     File.chmod(0400, @file)
     assert(!(File::Stat.new(@file).writable_real?))
@@ -1038,7 +1038,7 @@
   end
 
   def test_stat_world_writable_p
-    return if /cygwin|mswin|bccwin|mingw|emx/ =~ RUBY_PLATFORM
+    return if /cygwin|msys|mswin|bccwin|mingw|emx/ =~ RUBY_PLATFORM
     File.chmod(0006, @file)
     assert(File::Stat.new(@file).world_writable?)
     File.chmod(0060, @file)
@@ -1048,7 +1048,7 @@
   end
 
   def test_stat_executable_p
-    return if /cygwin|mswin|bccwin|mingw|emx/ =~ RUBY_PLATFORM
+    return if /cygwin|msys|mswin|bccwin|mingw|emx/ =~ RUBY_PLATFORM
     File.chmod(0100, @file)
     assert(File::Stat.new(@file).executable?)
     File.chmod(0600, @file)
@@ -1056,7 +1056,7 @@
   end
 
   def test_stat_executable_real_p
-    return if /cygwin|mswin|bccwin|mingw|emx/ =~ RUBY_PLATFORM
+    return if /cygwin|msys|mswin|bccwin|mingw|emx/ =~ RUBY_PLATFORM
     File.chmod(0100, @file)
     assert(File::Stat.new(@file).executable_real?)
     File.chmod(0600, @file)
@@ -1081,7 +1081,7 @@
   end
 
   def test_stat_owned_p ## xxx
-    return if /cygwin|mswin|bccwin|mingw|emx/ =~ RUBY_PLATFORM
+    return if /cygwin|msys|mswin|bccwin|mingw|emx/ =~ RUBY_PLATFORM
     assert(File::Stat.new(@file).owned?)
     assert(File::Stat.new(@file).grpowned?)
   end
diff -Naur ruby-2.0.0-p195-orig/test/ruby/test_path.rb ruby-2.0.0-p195/test/ruby/test_path.rb
--- ruby-2.0.0-p195-orig/test/ruby/test_path.rb	2011-10-26 06:24:29.000000000 +0000
+++ ruby-2.0.0-p195/test/ruby/test_path.rb	2013-05-22 06:32:23.909179700 +0000
@@ -47,7 +47,7 @@
   end
 
   def test_dirname
-    if /(bcc|ms)win\d|mingw|cygwin|emx/ =~ RUBY_PLATFORM
+    if /(bcc|ms)win\d|mingw|cygwin|msys|emx/ =~ RUBY_PLATFORM
       # DOSISH_DRIVE_LETTER
       assert_equal('C:.', File.dirname('C:'))
       assert_equal('C:.', File.dirname('C:a'))
@@ -103,7 +103,7 @@
     assert_equal('/', File.dirname('/a/'))
     assert_equal('/a', File.dirname('/a/b'))
 
-    if /(bcc|ms|cyg)win|mingw|emx/ =~ RUBY_PLATFORM
+    if /(bcc|ms|cyg)win|msys|mingw|emx/ =~ RUBY_PLATFORM
       # DOSISH_UNC
       assert_equal('//', File.dirname('//'))
       assert_equal('//a', File.dirname('//a'))
@@ -137,7 +137,7 @@
   end
 
   def test_basename
-    if /(bcc|ms)win\d|mingw|cygwin|emx/ =~ RUBY_PLATFORM
+    if /(bcc|ms)win\d|mingw|cygwin|msys|emx/ =~ RUBY_PLATFORM
       # DOSISH_DRIVE_LETTER
       assert_equal('', File.basename('C:'))
       assert_equal('a', File.basename('C:a'))
@@ -193,7 +193,7 @@
 
     assert_equal("..", File.basename("..", ".*"))
 
-    if /(bcc|ms|cyg)win|mingw|emx/ =~ RUBY_PLATFORM
+    if /(bcc|ms|cyg)win|msys|mingw|emx/ =~ RUBY_PLATFORM
       # DOSISH_UNC
       assert_equal('/', File.basename('//'))
       assert_equal('/', File.basename('//a'))
diff -Naur ruby-2.0.0-p195-orig/test/rubygems/test_gem_platform.rb ruby-2.0.0-p195/test/rubygems/test_gem_platform.rb
--- ruby-2.0.0-p195-orig/test/rubygems/test_gem_platform.rb	2012-11-29 06:52:18.000000000 +0000
+++ ruby-2.0.0-p195/test/rubygems/test_gem_platform.rb	2013-05-22 06:32:23.909179700 +0000
@@ -45,6 +45,7 @@
       'universal-darwin9'      => ['universal', 'darwin',    '9'],
       'universal-macruby'      => ['universal', 'macruby',   nil],
       'i386-cygwin'            => ['x86',       'cygwin',    nil],
+      'i386-msys'              => ['x86',       'msys',      nil],
       'i686-darwin'            => ['x86',       'darwin',    nil],
       'i686-darwin8.4.1'       => ['x86',       'darwin',    '8'],
       'i386-freebsd4.11'       => ['x86',       'freebsd',   '4'],
diff -Naur ruby-2.0.0-p195-orig/test/socket/test_addrinfo.rb ruby-2.0.0-p195/test/socket/test_addrinfo.rb
--- ruby-2.0.0-p195-orig/test/socket/test_addrinfo.rb	2012-10-30 00:40:54.000000000 +0000
+++ ruby-2.0.0-p195/test/socket/test_addrinfo.rb	2013-05-22 06:32:23.909179700 +0000
@@ -6,7 +6,7 @@
 require "test/unit"
 
 class TestSocketAddrinfo < Test::Unit::TestCase
-  HAS_UNIXSOCKET = defined?(UNIXSocket) && /cygwin/ !~ RUBY_PLATFORM
+  HAS_UNIXSOCKET = defined?(UNIXSocket) && /cygwin|msys/ !~ RUBY_PLATFORM
 
   def tcp_unspecified_to_loopback(addrinfo)
     if addrinfo.ipv4? && addrinfo.ip_address == "0.0.0.0"
diff -Naur ruby-2.0.0-p195-orig/test/socket/test_unix.rb ruby-2.0.0-p195/test/socket/test_unix.rb
--- ruby-2.0.0-p195-orig/test/socket/test_unix.rb	2013-01-31 04:59:31.000000000 +0000
+++ ruby-2.0.0-p195/test/socket/test_unix.rb	2013-05-22 06:32:23.924804700 +0000
@@ -598,4 +598,4 @@
     assert(s0.closed?)
   end
 
-end if defined?(UNIXSocket) && /cygwin/ !~ RUBY_PLATFORM
+end if defined?(UNIXSocket) && /cygwin|msys/ !~ RUBY_PLATFORM
diff -Naur ruby-2.0.0-p195-orig/test/webrick/test_cgi.rb ruby-2.0.0-p195/test/webrick/test_cgi.rb
--- ruby-2.0.0-p195-orig/test/webrick/test_cgi.rb	2012-11-06 00:49:57.000000000 +0000
+++ ruby-2.0.0-p195/test/webrick/test_cgi.rb	2013-05-22 06:32:23.940429700 +0000
@@ -20,7 +20,7 @@
         end
       },
     }
-    if RUBY_PLATFORM =~ /mswin32|mingw|cygwin|bccwin32/
+    if RUBY_PLATFORM =~ /mswin32|mingw|cygwin|msys|bccwin32/
       config[:CGIPathEnv] = ENV['PATH'] # runtime dll may not be in system dir.
     end
     TestWEBrick.start_httpserver(config){|server, addr, port, log|
@@ -40,7 +40,7 @@
       req = Net::HTTP::Get.new("/webrick.cgi/%A4%DB%A4%B2/%A4%DB%A4%B2")
       # Path info of res.body is passed via ENV.
       # ENV[] returns different value on Windows depending on locale.
-      unless RUBY_PLATFORM =~ /mswin32|mingw|cygwin|bccwin32/ &&
+      unless RUBY_PLATFORM =~ /mswin32|mingw|cygwin|msys|bccwin32/ &&
              Encoding.find("locale") != Encoding.find("filesystem")
         http.request(req){|res|
           assert_equal("/\xA4\xDB\xA4\xB2/\xA4\xDB\xA4\xB2", res.body, log.call)}
diff -Naur ruby-2.0.0-p195-orig/tool/config.guess ruby-2.0.0-p195/tool/config.guess
--- ruby-2.0.0-p195-orig/tool/config.guess	2012-01-29 13:50:18.000000000 +0000
+++ ruby-2.0.0-p195/tool/config.guess	2013-05-22 06:32:23.940429700 +0000
@@ -846,6 +846,9 @@
     amd64:CYGWIN*:*:* | x86_64:CYGWIN*:*:*)
 	echo x86_64-unknown-cygwin
 	exit ;;
+    amd64:MSYS*:*:* | x86_64:MSYS*:*:*)
+	echo x86_64-unknown-msys
+	exit ;;
     p*:CYGWIN*:*)
 	echo powerpcle-unknown-cygwin
 	exit ;;
diff -Naur ruby-2.0.0-p195-orig/win32/mkexports.rb ruby-2.0.0-p195/win32/mkexports.rb
--- ruby-2.0.0-p195-orig/win32/mkexports.rb	2012-11-12 05:29:52.000000000 +0000
+++ ruby-2.0.0-p195/win32/mkexports.rb	2013-05-22 06:32:23.940429700 +0000
@@ -158,6 +158,30 @@
   end
 end
 
+class Exports::Msys < Exports
+  def self.nm
+    @@nm ||= RbConfig::CONFIG["NM"]
+  end
+
+  def exports(*)
+    super()
+  end
+
+  def each_line(objs, &block)
+    IO.foreach("|#{self.class.nm} --extern --defined #{objs.join(' ')}", &block)
+  end
+
+  def each_export(objs)
+    symprefix = RbConfig::CONFIG["SYMBOL_PREFIX"]
+    symprefix.strip! if symprefix
+    re = /\s(?:(T)|[[:upper:]])\s#{symprefix}((?!Init_|.*_threadptr_|DllMain\b).*)$/
+    objdump(objs) do |l|
+      next if /@.*@/ =~ l
+      yield $2, !$1 if re =~ l
+    end
+  end
+end
+
 class Exports::Mingw < Exports::Cygwin
   def each_export(objs)
     super