build: autogen.sh: Use mkdir -p to suppress warning

It's minor but hey, warnings stand out.

1 files changed, 1 insertions, 1 deletions

diff --git a/autogen.sh b/autogen.sh
index 0a07bdf1..b38e34c6 100755
--- a/autogen.sh
+++ b/autogen.sh
@@ -36,7 +36,7 @@ EOF
 else
     # gtkdocize needs the macro directory to exist before
     # we call autoreconf
-    mkdir m4
+    mkdir -p m4
     gtkdocize || exit $?
 fi