diff --git a/CMakeLists.txt b/CMakeLists.txt
index d963e7c..a46b2c6 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -155,11 +155,6 @@ set(ZLIB_SRCS
     uncompr.c
     zutil.c)
 
-set_source_files_properties(
-    win32/zlib1.rc
-    PROPERTIES COMPILE_FLAGS
-               $<$<STREQUAL:${CMAKE_RC_OUTPUT_EXTENSION},.obj>:-DGCC_WINDRES>)
-
 if(WIN32)
     set(zlib_static_suffix "s")
     set(CMAKE_DEBUG_POSTFIX "d")
diff --git a/win32/Makefile.gcc b/win32/Makefile.gcc
index 081e391..35172fb 100644
--- a/win32/Makefile.gcc
+++ b/win32/Makefile.gcc
@@ -50,7 +50,7 @@ AR = $(PREFIX)ar
 ARFLAGS = rcs
 
 RC = $(PREFIX)windres
-RCFLAGS = --define GCC_WINDRES
+RCFLAGS =
 
 STRIP = $(PREFIX)strip
 
diff --git a/win32/zlib1.rc b/win32/zlib1.rc
index ceb4ee5..e4847d8 100644
--- a/win32/zlib1.rc
+++ b/win32/zlib1.rc
@@ -1,11 +1,8 @@
 #include <winver.h>
 #include "../zlib.h"
 
-#ifdef GCC_WINDRES
 VS_VERSION_INFO		VERSIONINFO
-#else
-VS_VERSION_INFO		VERSIONINFO	MOVEABLE IMPURE LOADONCALL DISCARDABLE
-#endif
+
   FILEVERSION		ZLIB_VER_MAJOR,ZLIB_VER_MINOR,ZLIB_VER_REVISION,0
   PRODUCTVERSION	ZLIB_VER_MAJOR,ZLIB_VER_MINOR,ZLIB_VER_REVISION,0
   FILEFLAGSMASK		VS_FFI_FILEFLAGSMASK