build: Remove support for non-pkg-config Expat

The Expat XML library has shipped a pkg-config file for long enough to
be in Debian's oldstable (Jessie, April 2015) and Ubuntu's oldest
supported LTS (Trusty, 14.04). The pkg-config file was added in Expat
upstream's commit 352cfc8f59a7, in September 2007.

Drop build support for versions of Expat which do not ship a
pkg-config file.

Signed-off-by: Daniel Stone <daniels@collabora.com>
Reviewed-by: Derek Foreman <derek.foreman.samsung@gmail.com>
Reviewed-by: Emil Velikov <emil.velikov@collabora.com>

diff --git a/configure.ac b/configure.ac
index 8c2fb82..0022dcd 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -111,16 +111,7 @@ if test "x$enable_libraries" = "xyes"; then
                      [[#include <time.h>]])
 fi
 
-PKG_CHECK_MODULES(EXPAT, [expat], [],
-       [AC_CHECK_HEADERS(expat.h, [],
-               [AC_MSG_ERROR([Can't find expat.h. Please install expat.])])
-        SAVE_LIBS="$LIBS"
-        AC_SEARCH_LIBS(XML_ParserCreate, expat, [],
-               [AC_MSG_ERROR([Can't find expat library. Please install expat.])])
-        EXPAT_LIBS="$LIBS"
-        LIBS="$SAVE_LIBS"
-        AC_SUBST(EXPAT_LIBS)
-       ])
+PKG_CHECK_MODULES(EXPAT, [expat])
 
 AM_CONDITIONAL([DTD_VALIDATION], [test "x$enable_dtd_validation" = "xyes"])
 if test "x$enable_dtd_validation" = "xyes"; then