Fix compilation with clang-cl on windows

zlib.h

@@ -31,12 +31,18 @@
 #ifndef ZLIB_H
 #define ZLIB_H
 
+/* Almost all content is uninteresting (or harmful) for the VS resource compiler. */
+#ifndef RC_INVOKED
+
 #include "zconf.h"
 
 #ifdef __cplusplus
 extern "C" {
 #endif
 
+/* Only the following few lines are interesting for the VS resource compiler. */
+#endif  /* RC_INVOKED */
+
 #define ZLIB_VERSION "1.3.1.1-motley"
 #define ZLIB_VERNUM 0x1311
 #define ZLIB_VER_MAJOR 1
@@ -44,6 +50,9 @@ extern "C" {
 #define ZLIB_VER_REVISION 1
 #define ZLIB_VER_SUBREVISION 1
 
+/* The rest of this file is again uninteresting for the VS resource compiler. */
+#ifndef RC_INVOKED
+
 /*
     The 'zlib' compression library provides in-memory compression and
   decompression functions, including integrity checks of the uncompressed data.
@@ -1950,4 +1959,6 @@ ZEXTERN int            ZEXPORTVA gzvprintf(gzFile file,
 }
 #endif
 
+#endif  /* RC_INVOKED */
+
 #endif /* ZLIB_H */