Fixing the Windows Build

engine/lib/zlib/gzlib.c

@@ -4,7 +4,9 @@
  */
 
 #include "gzguts.h"
+#if defined(_MAC)
 #include "unistd.h"
+#endif
 
 #if defined(_WIN32) && !defined(__BORLANDC__) && !defined(__MINGW32__)
 #  define LSEEK _lseeki64

engine/lib/zlib/gzread.c

@@ -4,7 +4,9 @@
  */
 
 #include "gzguts.h"
+#if defined(_MAC)
 #include "unistd.h"
+#endif
 
 /* Local functions */
 local int gz_load OF((gz_statep, unsigned char *, unsigned, unsigned *));

engine/lib/zlib/gzwrite.c

@@ -4,7 +4,9 @@
  */
 
 #include "gzguts.h"
+#if defined(_MAC)
 #include "unistd.h"
+#endif
 
 /* Local functions */
 local int gz_init OF((gz_statep));