Cleanup after ZLIB_WINAPI check

Clear CMAKE_REQUIRED_(INCLUDES|LIBRARIES) so that the rest of the checks
after this one do not try to link zlib.

SVN-Revision: 4133

CMakeLists.txt

@@ -204,6 +204,8 @@ IF(ZLIB_FOUND)
     CHECK_C_SOURCE_Runs(
       "#ifndef ZLIB_WINAPI\n#define ZLIB_WINAPI\n#endif\n#include <zlib.h>\nint main() {uLong f = zlibCompileFlags(); return (f&(1U<<10))?0:-1; }"
       ZLIB_WINAPI)
+    SET(CMAKE_REQUIRED_INCLUDES)
+    SET(CMAKE_REQUIRED_LIBRARIES)
   ENDIF(WIN32 AND NOT CYGWIN)
 ENDIF(ZLIB_FOUND)
 MARK_AS_ADVANCED(CLEAR ZLIB_INCLUDE_DIR)