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/aclocal/ax_lib_event.m4 b/lib/cpp/aclocal/ax_lib_event.m4
index 14f115e..9266df4 100644
--- a/lib/cpp/aclocal/ax_lib_event.m4
+++ b/lib/cpp/aclocal/ax_lib_event.m4
@@ -1,6 +1,6 @@
 dnl @synopsis AX_LIB_EVENT([MINIMUM-VERSION])
 dnl
-dnl Test for the libz library of a particular version (or newer).
+dnl Test for the libevent library of a particular version (or newer).
 dnl
 dnl If no path to the installed libevent is given, the macro will first try
 dnl using no -I or -L flags, then searches under /usr, /usr/local, /opt,