Create the m4 directory, and also place .gitignore in there for libtool.

patch by Jan Engelhardt (jengelh at medozas dot de)

Fixes the error:
aclocal: couldn't open directory "m4": No such file or directory
autoreconf: aclocal failed with exit status: 1

Change-Id: I1c1cd2c3d96f0d7d25616ec084dfc9bf9077fd4f
1 file changed