[gegl] configure.ac: require libavutil for Windows build

[Øyvind "pippin" Kolås <ok src gnome org>]

commit 929a7fdc271caa94577c582c9697eeb80d25f453
Author: Edward E <develinthedetail gmail com>
Date:   Sat Mar 30 22:04:50 2019 -0500

    configure.ac: require libavutil for Windows build

 configure.ac | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index 69c831a5c..9464f8fe4 100644
--- a/configure.ac
+++ b/configure.ac
@@ -65,6 +65,7 @@ m4_define([pygobject3_required_version], [3.2])
 m4_define([vapigen_required_version], [0.20.0])
 m4_define([libavformat_required_version], [55.48.100])
 m4_define([libavcodec_required_version], [55.69.100])
+m4_define([libavutil_required_version], [52.92.100])
 m4_define([libswscale_required_version], [2.6.100])
 
 AC_INIT(gegl, gegl_major_version.gegl_minor_version.gegl_micro_version)
@@ -1071,9 +1072,9 @@ AC_SUBST(LUA_LIBS)
 AC_ARG_WITH(libavformat,  [  --without-libavformat   build without libavformat support])
 
 if test "x$with_libavformat" != xno; then
-  PKG_CHECK_MODULES(AVFORMAT, libavformat >= libavformat_required_version libavcodec >= 
libavcodec_required_version libswscale >= libswscale_required_version,
+  PKG_CHECK_MODULES(AVFORMAT, libavformat >= libavformat_required_version libavcodec >= 
libavcodec_required_version libavutil >= libavutil_required_version libswscale >= libswscale_required_version,
     have_libavformat="yes",
-    have_libavformat="no  (sufficiently new libavformat / libavcodec or libswcale not found)")
+    have_libavformat="no  (sufficiently new libavformat / libavcodec / libavutil or libswcale not found)")
   # verify the presence of the avformat.h header
   if test "x$have_libavformat" = "xyes"; then
     gegl_save_CPPFLAGS=$CPPFLAGS