+/* provide 64-bit offset functions if _LARGEFILE64_SOURCE defined, and/or
+ * change the regular functions to 64 bits if _FILE_OFFSET_BITS is 64 (if
+ * both are true, the application gets the *64 functions, and the regular
+ * functions are changed to 64 bits) -- in case these are set on systems
+ * without large file support, _LFS64_LARGEFILE must also be true
+ */
+#if defined(_LARGEFILE64_SOURCE) && _LFS64_LARGEFILE-0
+ ZEXTERN gzFile ZEXPORT gzopen64 OF((const char *, const char *));
+ ZEXTERN z_off64_t ZEXPORT gzseek64 OF((gzFile, z_off64_t, int));
+ ZEXTERN z_off64_t ZEXPORT gztell64 OF((gzFile));
+ ZEXTERN z_off64_t ZEXPORT gzoffset64 OF((gzFile));
+ ZEXTERN uLong ZEXPORT adler32_combine64 OF((uLong, uLong, z_off64_t));
+ ZEXTERN uLong ZEXPORT crc32_combine64 OF((uLong, uLong, z_off64_t));
+#endif
+
+#if !defined(ZLIB_INTERNAL) && _FILE_OFFSET_BITS-0 == 64 && _LFS64_LARGEFILE-0
+# define gzopen gzopen64
+# define gzseek gzseek64
+# define gztell gztell64
+# define gzoffset gzoffset64
+# define adler32_combine adler32_combine64
+# define crc32_combine crc32_combine64
+# ifdef _LARGEFILE64_SOURCE
+ ZEXTERN gzFile ZEXPORT gzopen64 OF((const char *, const char *));
+ ZEXTERN z_off_t ZEXPORT gzseek64 OF((gzFile, z_off_t, int));
+ ZEXTERN z_off_t ZEXPORT gztell64 OF((gzFile));
+ ZEXTERN z_off_t ZEXPORT gzoffset64 OF((gzFile));
+ ZEXTERN uLong ZEXPORT adler32_combine64 OF((uLong, uLong, z_off_t));
+ ZEXTERN uLong ZEXPORT crc32_combine64 OF((uLong, uLong, z_off_t));
+# endif
+#else
+ ZEXTERN gzFile ZEXPORT gzopen OF((const char *, const char *));
+ ZEXTERN z_off_t ZEXPORT gzseek OF((gzFile, z_off_t, int));
+ ZEXTERN z_off_t ZEXPORT gztell OF((gzFile));
+ ZEXTERN z_off_t ZEXPORT gzoffset OF((gzFile));
+ ZEXTERN uLong ZEXPORT adler32_combine OF((uLong, uLong, z_off_t));
+ ZEXTERN uLong ZEXPORT crc32_combine OF((uLong, uLong, z_off_t));
+#endif