Avoid compiler complaints if _TIME_BITS defined when building zlib.
zlib does not use time_t, so _TIME_BITS is irrelevant. However it
may be defined anyway as part of a sledgehammer indiscriminately
applied to all builds.
diff --git a/gzguts.h b/gzguts.h
index e23f831..f937504 100644
--- a/gzguts.h
+++ b/gzguts.h
@@ -7,9 +7,8 @@
# ifndef _LARGEFILE_SOURCE
# define _LARGEFILE_SOURCE 1
# endif
-# ifdef _FILE_OFFSET_BITS
-# undef _FILE_OFFSET_BITS
-# endif
+# undef _FILE_OFFSET_BITS
+# undef _TIME_BITS
#endif
#ifdef HAVE_HIDDEN
