Fix recursing into subdirs of directories not enabled for automake recursion

As reported failing in gtk+/gdk/win32/rc by Jasper.
Respect AC_CONFIG_AUX_DIR and AC_CONFIG_HEADERS
Fix auxdir
Fix the case of empty AC_CONFIG_AUX_DIR
Merge pull request #6 from pwithnall/master

Add basic Vala support
Remove $RECHECK_LOGS

New automake parallel test harness stuff...

http://www.gnu.org/software/automake/manual/html_node/Parallel-Test-Harness.html

https://github.com/behdad/git.mk/issues/8
Improve parallel-test-suite cleanup

https://github.com/behdad/git.mk/issues/8
Trigger the libtool rules if gtk-doc uses it

gtk-doc may use libtool to build and run the `gtkdoc-scangobj` helper
programs but does so without defining the LTCOMPILE variable, causing
the libtool detection logic to fail and .libs directories do not get
added to the ignore list.

Since there's no explicit variable telling us if GTK_DOC_USE_LIBTOOL was
set, rely on GTKDOC_RUN being unset when libtool is not used.
Merge pull request #9 from em-/master

Trigger the libtool rules if gtk-doc uses it
Support --flavor no-tmpl gtk-doc

Will trigger us to ignore tmpl/.
Ignore automake parallel-tests test-driver
Improve GITIGNORE_MAINTAINERCLEANFILES_M4_LIBTOOL
Support Vala-generated C header files in subdirectories

valac can generate C header files using its --header option. If the
--includedir option is also specified, the header file will be generated
in the given (sub)directory. git.mk previously assumed all generated
header files were in the current directory. This change fixes that so it
gets the full header file path from $(DIST_COMMON).