For your convenience and allowed by zlib's license terms:
http://www.gzip.org/zlib/zlib_license.html a copy of the zlib source
-is bundled with SimGear. You must have zlib installed before you can
-build SimGear.
+is bundled with SimGear in $(top_srcdir)/src-libs/. You must have
+zlib installed before you can build SimGear.
- Most linux distributions have a zlib package. For linux
developers, we recommend ysou install your distributions package