Support zlib in non-standard path on Unix

Found by: Michael Osipov
Fixes: SERF-180

* SConstruct: Add ZLIB path in non-win32 case


git-svn-id: https://svn.apache.org/repos/asf/serf/trunk@1761040 13f79535-47bb-0310-9956-ffa450edef68
1 file changed