[gimp] Issue #2454: recent libwmf uses pkg-config.

[Jehan <jehanp src gnome org>]

commit df4e35a846b2368d02aafe9e87f907456f9b6c28
Author: Massimo Valentini <mvalentini src gnome org>
Date:   Thu Nov 8 11:39:30 2018 +0100

    Issue #2454: recent libwmf uses pkg-config.

 configure.ac | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)
---
diff --git a/configure.ac b/configure.ac
index b39e20747c..7bfccdc972 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1991,7 +1991,10 @@ if test "x$with_wmf" != xno; then
       WMF_LIBS=`$WMF_CONFIG --libs`
       WMF_CFLAGS=`$WMF_CONFIG --cflags`
     else
-      have_libwmf="no (libwmf is too old)"
+      have_libwmf=yes
+      PKG_CHECK_MODULES(WMF, libwmf >= wmf_required_version,
+                        FILE_WMF='file-wmf$(EXEEXT)',
+                        have_libwmf="no (libwmf not found)")
    fi
   else
     have_libwmf="no (libwmf not found)"