[glib] Check for zlib using pkg-config

[Matthias Clasen <matthiasc src gnome org>]

commit 1e8656fe24e846f3bb0533e96afb1e0b46a37b49
Author: Matthias Clasen <mclasen redhat com>
Date:   Thu Jul 8 14:12:28 2010 -0400

    Check for zlib using pkg-config
    
    Based on a patch by Felipe Contreras, see bug 623473.

 configure.in |   14 ++++++++------
 1 files changed, 8 insertions(+), 6 deletions(-)
---
diff --git a/configure.in b/configure.in
index 437d34b..7925026 100644
--- a/configure.in
+++ b/configure.in
@@ -460,14 +460,16 @@ AC_MSG_RESULT($enable_iconv_cache)
 dnl
 dnl zlib support
 dnl
-found_zlib=no
-AC_CHECK_LIB(z, inflate, [AC_CHECK_HEADER(zlib.h, found_zlib=yes)])
-
+PKG_CHECK_MODULES([ZLIB], [zlib], [found_zlib=yes], [found_zlib=no])
 if test "x$found_zlib" = "xno" ; then
-   AC_MSG_ERROR([*** Working zlib library and headers not found ***])
+  AC_CHECK_LIB(z, inflate, [AC_CHECK_HEADER(zlib.h, found_zlib=yes)])
+  if test "x$found_zlib" = "xno" ; then
+    AC_MSG_ERROR([*** Working zlib library and headers not found ***])
+  fi
+  ZLIB_LIBS='-lz'
+  AC_SUBST(ZLIB_LIBS)
 fi
-ZLIB_LIBS='-lz'
-AC_SUBST(ZLIB_LIBS)
+
 dnl
 dnl gettext support
 dnl