Makefile: Fix build by creating directories using -D
With the introduction of
46246030946d82b00e2a403c7f44783a97842767
we used the -D option to create our directory. This fails if the
directory doesnot exists. As a result of that change, we were
not able to successfully build gc-utils as a debian package
as dpkg-buildpackage doesnot create the manpage directory.
Therefore we use the -D option in a right way now, so we
can build debian packages again.
Signed-off-by: David Soria Parra <dsp@php.net>