Execute 'aclocal' when generating configuration files

This enables us to use pkg-config when looking for packages.

Reimplement 'autogen.sh' with 'autoreconf -f' would have been a
possibility, though it was discussed before and found unsuitable.
See: <#1625>

Author: havardAasen

src/.gitignore

@@ -3,6 +3,7 @@
 /.tmp_versions
 /Makefile.inc
 /Makefile.modinc
+/aclocal.m4
 /config.guess
 /config.h
 /config.log

src/autogen.sh

@@ -8,6 +8,7 @@ case :$AUTOGEN_TARGET: in
     [ -e config.guess ] || cp $automake_libdir/config.guess .
     [ -e config.sub ] || cp $automake_libdir/config.sub .
     [ -e install-sh ] || cp $automake_libdir/install-sh .
+    aclocal --force
     autoconf
     # autoconf only updates the timestamp if the output actually changed.
     # The target's timestamp must be updated or make is confused