diff --git a/mozilla/modules/libimg/png/pngconf.h b/mozilla/modules/libimg/png/pngconf.h
index 325d2de17f1..a6c2c75ec4f 100644
--- a/mozilla/modules/libimg/png/pngconf.h
+++ b/mozilla/modules/libimg/png/pngconf.h
@@ -1262,8 +1262,15 @@ typedef z_stream FAR *  png_zstreamp;
 #     endif
 #  endif  /* PNG_IMPEXP */
 #else /* !(DLL || non-cygwin WINDOWS) */
-#   if (defined(__IBMC__) || defined(__IBMCPP__)) && defined(__OS2__)
-#      ifndef PNGAPI
+#   if defined(__OS2__)
+#      if defined(__GNUC__) && defined(__declspec) && defined(PNG_DLL) && !defined(PNG_IMPEXP)
+#         ifdef PNG_BUILD_DLL
+#            define PNG_IMPEXP __declspec(dllexport)
+#         else
+#            define PNG_IMPEXP __declspec(dllimport)
+#         endif
+#      endif /* GNUC & declspec */
+#      if (defined(__IBMC__) || defined(__IBMCPP__)) && !defined(PNGAPI)
 #         define PNGAPI _System
 #      endif
 #   else
diff --git a/mozilla/modules/libjar/zipstub.h b/mozilla/modules/libjar/zipstub.h
index 8b54005f6cd..78f6add0738 100644
--- a/mozilla/modules/libjar/zipstub.h
+++ b/mozilla/modules/libjar/zipstub.h
@@ -78,6 +78,9 @@
 #elif defined(XP_WIN)
 #define PR_EXTERN(__type)       extern _declspec(dllexport) __type
 #define PR_PUBLIC_API(__type)   _declspec(dllexport) __type
+#elif defined(XP_OS2) && defined(__declspec)
+#define PR_EXTERN(__type)       extern __declspec(dllexport) __type
+#define PR_PUBLIC_API(__type)   __declspec(dllexport) __type
 #else /* XP_UNIX */
 #define PR_EXTERN(__type)       extern __type
 #define PR_PUBLIC_API(__type)   __type 
diff --git a/mozilla/modules/libreg/include/NSReg.h b/mozilla/modules/libreg/include/NSReg.h
index 9b606ffd116..f26a917eae8 100644
--- a/mozilla/modules/libreg/include/NSReg.h
+++ b/mozilla/modules/libreg/include/NSReg.h
@@ -127,6 +127,8 @@ typedef struct _reginfo
   #else
   #define VR_INTERFACE(type)     type _far _pascal _export
   #endif
+#elif defined(XP_OS2) && defined(__declspec)
+  #define VR_INTERFACE(type)     __declspec(dllexport) type
 #elif defined XP_MAC
   #define VR_INTERFACE(__x)  __declspec(export) __x
 #elif defined (HAVE_VISIBILITY_ATTRIBUTE)
diff --git a/mozilla/modules/zlib/src/Makefile.in b/mozilla/modules/zlib/src/Makefile.in
index bf0c0f53737..7f6f7b5f847 100644
--- a/mozilla/modules/zlib/src/Makefile.in
+++ b/mozilla/modules/zlib/src/Makefile.in
@@ -60,7 +60,7 @@ endif
 endif
 endif
 
-ifeq (,$(filter-out WINNT WINCE,$(OS_ARCH)))
+ifeq (,$(filter-out WINNT WINCE OS2,$(OS_ARCH)))
 DEFINES	+= -DZLIB_DLL=1
 endif
 
diff --git a/mozilla/modules/zlib/src/zconf.h b/mozilla/modules/zlib/src/zconf.h
index dd32fec122d..eda0459ec85 100644
--- a/mozilla/modules/zlib/src/zconf.h
+++ b/mozilla/modules/zlib/src/zconf.h
@@ -3,7 +3,7 @@
  * For conditions of distribution and use, see copyright notice in zlib.h
  */
 
-/* @(#) $Id: zconf.h,v 3.9 2005-08-04 19:14:14 tor%cs.brown.edu Exp $ */
+/* @(#) $Id: zconf.h,v 3.10 2006-03-08 19:21:35 mkaply%us.ibm.com Exp $ */
 
 #ifndef ZCONF_H
 #define ZCONF_H
@@ -234,6 +234,18 @@
 #  endif
 #endif
 
+#if defined(__OS2__) && defined(__declspec)
+#  ifdef ZLIB_DLL
+#    ifdef ZLIB_INTERNAL
+#      define ZEXPORT   __declspec(dllexport)
+#      define ZEXPORTVA __declspec(dllexport)
+#    else
+#      define ZEXPORT   __declspec(dllimport)
+#      define ZEXPORTVA __declspec(dllimport)
+#    endif
+#  endif
+#endif
+
 #if defined (__BEOS__)
 #  ifdef ZLIB_DLL
 #    ifdef ZLIB_INTERNAL
diff --git a/mozilla/sun-java/stubs/include/jni_md.h b/mozilla/sun-java/stubs/include/jni_md.h
index 3c8c63d9913..cf6eb8cf327 100644
--- a/mozilla/sun-java/stubs/include/jni_md.h
+++ b/mozilla/sun-java/stubs/include/jni_md.h
@@ -98,20 +98,8 @@
  ******************************************************************************/
 
 /* DLL Entry modifiers... */
-#if defined(XP_OS2)
-#  ifdef XP_OS2_VACPP
-#     define JNI_PUBLIC_API(ResultType)      ResultType _System
-#     define JNI_PUBLIC_VAR(VarType)         VarType
-#     define JNICALL                         _Optlink
-#     define JNIEXPORT
-#  else
-#     define JNI_PUBLIC_API(ResultType)	   ResultType
-#     define JNI_PUBLIC_VAR(VarType)         VarType
-#     define JNICALL
-#     define JNIEXPORT
-#  endif
 /* Win32 */
-#elif defined(XP_WIN) || defined(_WINDOWS) || defined(WIN32) || defined(_WIN32)
+#if defined(XP_WIN) || defined(_WINDOWS) || defined(WIN32) || defined(_WIN32)
 #	include <windows.h>
 #	if defined(_MSC_VER) || defined(__GNUC__)
 #		if defined(WIN32) || defined(_WIN32)
@@ -153,6 +141,28 @@
 	/*  This is the stuff inherited from JavaSoft .. */
 #	define JNIEXPORT __declspec(dllexport)
 
+/* OS/2 */
+#elif defined(XP_OS2)
+#	ifdef XP_OS2_VACPP
+#		define JNI_PUBLIC_API(ResultType)	ResultType _System
+#		define JNI_PUBLIC_VAR(VarType)		VarType
+#		define JNICALL				_Optlink
+#		define JNIEXPORT
+#	elif defined(__declspec)
+#		define JNI_PUBLIC_API(ResultType)	__declspec(dllexport) ResultType
+#		define JNI_PUBLIC_VAR(VarType)		VarType
+#		define JNI_NATIVE_STUB(ResultType)	__declspec(dllexport) ResultType
+#		define JNICALL
+#		define JNIEXPORT
+#	else
+#		define JNI_PUBLIC_API(ResultType)	ResultType
+#		define JNI_PUBLIC_VAR(VarType)		VarType
+#		define JNICALL
+#		define JNIEXPORT
+#	endif
+#	ifndef IS_LITTLE_ENDIAN
+#		define IS_LITTLE_ENDIAN
+#	endif
 
 /* Mac */
 #elif macintosh || Macintosh || THINK_C
diff --git a/mozilla/sun-java/stubs/include/jri_md.h b/mozilla/sun-java/stubs/include/jri_md.h
index 2514ec29036..950481de35b 100644
--- a/mozilla/sun-java/stubs/include/jri_md.h
+++ b/mozilla/sun-java/stubs/include/jri_md.h
@@ -68,18 +68,8 @@ extern "C" {
 
 /* DLL Entry modifiers... */
 
-/* PC */
-#if defined(XP_OS2)
-#  ifdef XP_OS2_VACPP
-#	  define JRI_PUBLIC_API(ResultType)	    ResultType _Optlink
-#	  define JRI_PUBLIC_VAR(VarType)        VarType
-#     define JRI_CALLBACK
-#  else
-#	  define JRI_PUBLIC_API(ResultType)	    ResultType
-#	  define JRI_PUBLIC_VAR(VarType)        VarType
-#     define JRI_CALLBACK
-#  endif
-#elif defined(XP_WIN) || defined(_WINDOWS) || defined(WIN32) || defined(_WIN32)
+/* Windows */
+#if defined(XP_WIN) || defined(_WINDOWS) || defined(WIN32) || defined(_WIN32)
 #	include <windows.h>
 #	if defined(_MSC_VER) || defined(__GNUC__)
 #		if defined(WIN32) || defined(_WIN32)
@@ -129,6 +119,25 @@ extern "C" {
 #		define IS_LITTLE_ENDIAN
 #	endif
 
+/* OS/2 */
+#elif defined(XP_OS2)
+#	ifdef XP_OS2_VACPP
+#		define JRI_PUBLIC_API(ResultType)	ResultType _Optlink
+#		define JRI_PUBLIC_VAR(VarType)		VarType
+#     		define JRI_CALLBACK
+#	elif defined(__declspec)
+#		define JRI_PUBLIC_API(ResultType)  	__declspec(dllexport) ResultType
+#		define JRI_PUBLIC_VAR(VarType)	   	VarType
+#		define JRI_PUBLIC_VAR_EXP(VarType) 	__declspec(dllexport) VarType
+#		define JRI_PUBLIC_VAR_IMP(VarType) 	__declspec(dllimport) VarType
+#		define JRI_NATIVE_STUB(ResultType) 	__declspec(dllexport) ResultType
+#		define JRI_CALLBACK
+#	else
+#		define JRI_PUBLIC_API(ResultType)	ResultType
+#		define JRI_PUBLIC_VAR(VarType)		VarType
+#		define JRI_CALLBACK
+#	endif
+
 /* Mac */
 #elif defined (macintosh) || Macintosh || THINK_C
 #	if defined(__MWERKS__)				/* Metrowerks */
diff --git a/mozilla/toolkit/library/Makefile.in b/mozilla/toolkit/library/Makefile.in
index e0b3c2bf171..b01b48cd738 100644
--- a/mozilla/toolkit/library/Makefile.in
+++ b/mozilla/toolkit/library/Makefile.in
@@ -68,6 +68,10 @@ ifeq ($(OS_ARCH)_$(GNU_CC),WINNT_)
 CPPSRCS += dlldeps-xul.cpp
 endif
 
+ifeq ($(OS_ARCH),OS2)
+CPPSRCS += dlldeps-xul.cpp
+endif
+
 # dependent libraries
 STATIC_LIBS = \
 	xulapp_s \
diff --git a/mozilla/toolkit/library/libxul-config.mk b/mozilla/toolkit/library/libxul-config.mk
index a39aff83047..9cfdeb64e89 100644
--- a/mozilla/toolkit/library/libxul-config.mk
+++ b/mozilla/toolkit/library/libxul-config.mk
@@ -60,10 +60,27 @@ endif
 LOCAL_INCLUDES += -I$(topsrcdir)/widget/src/windows
 endif
 
-ifeq ($(OS_ARCH),WINNT)
+ifneq (,$(filter WINNT OS2,$(OS_ARCH)))
 DEFINES	+= -DZLIB_DLL=1
 endif
 
+ifeq ($(OS_ARCH),OS2)
+REQUIRES += libreg widget gfx
+
+CPPSRCS += \
+	dlldeps.cpp \
+	dlldeps-obs.cpp \
+	nsGFXDeps.cpp \
+	$(NULL)
+
+ifndef MOZ_NATIVE_ZLIB
+CPPSRCS += dlldeps-zlib.cpp
+DEFINES += -DZLIB_INTERNAL
+endif
+
+LOCAL_INCLUDES += -I$(topsrcdir)/widget/src/os2
+endif
+
 # dependent libraries
 STATIC_LIBS += \
 	xpcom_core \
diff --git a/mozilla/xpcom/build/Makefile.in b/mozilla/xpcom/build/Makefile.in
index 08e3a788d2b..dee18bd674d 100644
--- a/mozilla/xpcom/build/Makefile.in
+++ b/mozilla/xpcom/build/Makefile.in
@@ -92,6 +92,12 @@ CPPSRCS		+= dlldeps.cpp
 endif
 endif
 
+ifndef MINIMO
+ifeq ($(OS_ARCH)$(MOZ_ENABLE_LIBXUL),OS2)
+CPPSRCS		+= dlldeps.cpp
+endif
+endif
+
 ifdef XPCOM_USE_LEA
 CSRCS += malloc.c
 endif
diff --git a/mozilla/xpcom/build/dlldeps.cpp b/mozilla/xpcom/build/dlldeps.cpp
index 812b7ec8af2..9f438c1b899 100644
--- a/mozilla/xpcom/build/dlldeps.cpp
+++ b/mozilla/xpcom/build/dlldeps.cpp
@@ -38,7 +38,9 @@
 // Force references to all of the symbols that we want exported from
 // the dll that are located in the .lib files we link with
 
+#ifndef XP_OS2
 #include <windows.h>
+#endif
 #include "nsXPCOMGlue.h"
 #include "nsVoidArray.h"
 #include "nsValueArray.h"
@@ -95,7 +97,7 @@
 #include "nsStringBuffer.h"
 #include "nsCategoryCache.h"
 
-#ifndef WINCE
+#if !defined(WINCE) && !defined(XP_OS2)
 #include "nsWindowsRegKey.h"
 #endif
 
@@ -152,7 +154,7 @@ void XXXNeverCalled()
     NS_ProxyRelease(nsnull, nsnull, PR_FALSE);
     XPT_DoString(nsnull, nsnull, nsnull);
     XPT_DoHeader(nsnull, nsnull, nsnull);
-#if defined (DEBUG) && !defined (WINCE)
+#if defined (DEBUG) && !defined (WINCE) && !defined(XP_OS2)
     PurePrintf(0);
 #endif
     XPTC_InvokeByIndex(nsnull, 0, 0, nsnull);
@@ -261,7 +263,7 @@ void XXXNeverCalled()
       b.ToString(0, y);
     }
 
-#ifndef WINCE
+#if !defined(WINCE) && !defined(XP_OS2)
     NS_NewWindowsRegKey(nsnull);
 #endif
 }