autogen.sh: Ensure we have m4 directory

This is a regression introduced by the previous commit.

diff --git a/autogen.sh b/autogen.sh
index 88ce246..e8cfe3e 100755 (executable)
--- a/autogen.sh
+++ b/autogen.sh
@@ -13,6 +13,7 @@ if test -z $AUTORECONF; then
         exit 1
 fi
 
+mkdir -p m4
 autoreconf --force --install --verbose || exit $?
 
 cd "$olddir"