2.5: warning fixes

Mostly harmless ones, except for one about "gzopen64" being
undeclared. This needs some defines in BLI_storage.h to be set
before <unistd.h> is included. Might fix a crash in compressed
file reading, though I'm not sure since it's hard to repeat
the crash consistently.

source/blender/blenloader/intern/readblenentry.c

@@ -32,6 +32,8 @@
 #include <config.h>
 #endif
 
+#include "BLI_storage.h" /* _LARGEFILE_SOURCE */
+
 #include <stdlib.h>
 #include <string.h>
 #include <stdio.h>