diff -Naur zlib-1.2.11-pure/zconf.h.in zlib-1.2.11/zconf.h.in
--- zlib-1.2.11-pure/zconf.h.in	2013-04-28 23:57:11.000000000 +0100
+++ zlib-1.2.11/zconf.h.in	2015-03-15 22:45:37.900299300 +0000
@@ -481,7 +481,7 @@
 #  define z_off_t long
 #endif
 
-#if !defined(_WIN32) && defined(Z_LARGE64)
+#if (defined(_WIN32) && defined(__GNUC__) && defined(_LARGEFILE64_SOURCE)) || defined(Z_LARGE64)
 #  define z_off64_t off64_t
 #else
 #  if defined(_WIN32) && !defined(__GNUC__) && !defined(Z_SOLO)
diff -Naur zlib-1.2.11-pure/zconf.h.cmakein zlib-1.2.11/zconf.h.cmakein
--- zlib-1.2.11-pure/zconf.h.cmakein	2013-04-28 23:57:11.000000000 +0100
+++ zlib-1.2.11/zconf.h.cmakein	2015-03-15 22:45:37.900299300 +0000
@@ -481,7 +481,7 @@
 #  define z_off_t long
 #endif
 
-#if !defined(_WIN32) && defined(Z_LARGE64)
+#if (defined(_WIN32) && defined(__GNUC__) && defined(_LARGEFILE64_SOURCE)) || defined(Z_LARGE64)
 #  define z_off64_t off64_t
 #else
 #  if defined(_WIN32) && !defined(__GNUC__) && !defined(Z_SOLO)