Create a dummy m4 directory to make autoreconf --install --force work

Even when removing AC_CONFIG_MACRO_DIR aclocal insisted that it
needs to have a m4 directory. Make it happy by providing one. As git
is not tracking directories I needed to add a dummy file.

diff --git a/m4/DUMMY b/m4/DUMMY
new file mode 100644 (file)
index 0000000..fda557a
--- /dev/null
+++ b/m4/DUMMY
@@ -0,0 +1 @@
+Dummply placeholder.