Check for zlib.h

Signed-off-by: Ralph Castain <rhc@open-mpi.org>

configure.ac

@@ -19,7 +19,7 @@
 # Copyright (c) 2012      Oracle and/or its affiliates.  All rights reserved.
 # Copyright (c) 2013      Mellanox Technologies, Inc.
 #                         All rights reserved.
-# Copyright (c) 2013-2014 Intel, Inc.  All rights reserved.
+# Copyright (c) 2013-2017 Intel, Inc.  All rights reserved.
 # Copyright (c) 2014-2016 Research Organization for Information Science
 #                         and Technology (RIST). All rights reserved.
 # Copyright (c) 2016      IBM Corporation.  All rights reserved.
@@ -597,7 +597,7 @@ AC_CHECK_HEADERS([alloca.h aio.h arpa/inet.h dirent.h \
     sys/types.h sys/uio.h sys/un.h net/uio.h sys/utsname.h sys/vfs.h sys/wait.h syslog.h \
     termios.h ulimit.h unistd.h util.h utmp.h malloc.h \
     ifaddrs.h crt_externs.h regex.h mntent.h paths.h \
-    ioLib.h sockLib.h hostLib.h shlwapi.h sys/synch.h db.h ndbm.h])
+    ioLib.h sockLib.h hostLib.h shlwapi.h sys/synch.h db.h ndbm.h zlib.h])
 
 AC_CHECK_HEADERS([sys/mount.h], [], [],
 [AC_INCLUDES_DEFAULT