m4_ifnblank seems to be too new for some autoconf

And bumping autoconf version seems to be a bit much for such a small improvement

diff --git a/m4/with_pkg.m4 b/m4/with_pkg.m4
index 16a31655d03f29f205c701bb29938b5384cd9e07..60b2b05802f2851a852c0e7ea0ed5afe7fe293a2 100644 (file)
--- a/m4/with_pkg.m4
+++ b/m4/with_pkg.m4
@@ -87,7 +87,7 @@ m4_pushdef([enable_arg], m4_tolower([$1]))
 
 PKG_WITH_MODULES([$1],[$3],
     VLC_ADD_PLUGIN(module_name)
-    m4_ifnblank( [$8],  VLC_ADD_CPPFLAGS(module_name, [$8]))
+    m4_ifval( m4_normalize([$8]), VLC_ADD_CPPFLAGS(module_name, [$8]))
     VLC_ADD_CFLAGS(module_name,[$$1_CFLAGS] [$6])
     VLC_ADD_LIBS(module_name,[$$1_LIBS] [$7]),
     AS_IF([test x"$AS_TR_SH([enable_]enable_arg)" = "xyes"],