Thrift: Re-committing zlib.

Summary:
Same as the last (reverted) zlib patch,
but this time with way more awesome support for building
with no zlib headers installed.

Reviewed By: mcslee

Test Plan:
- Did lots of really pathological stuff in my VMware.
- On devrs004:
  ./bootstrap.sh && ./configure && make && make install DESTDIR=/tmp/tzinst && echo "Yay"

Revert Plan: ok


git-svn-id: https://svn.apache.org/repos/asf/incubator/thrift/trunk@665269 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/lib/cpp/configure.ac b/lib/cpp/configure.ac
index 5e33617..d9a66da 100644
--- a/lib/cpp/configure.ac
+++ b/lib/cpp/configure.ac
@@ -71,6 +71,9 @@
 AX_LIB_EVENT([1.0])
 AM_CONDITIONAL([AMX_HAVE_LIBEVENT], [test "$success" = "yes"])
 
+AX_LIB_ZLIB([1.2.3])
+AM_CONDITIONAL([AMX_HAVE_ZLIB], [test "$success" = "yes"])
+
 AC_CHECK_LIB(pthread, pthread_create)
 
 AC_CHECK_LIB(rt, sched_get_priority_min)