If the gf_methods was not found, the test would silently succeed doing
nothing. Check for existence and fail if it is not in the path.
Signed-off-by: Loic Dachary <loic@dachary.org>
* Update the README accordingly
* Add the VALGRIND variable to run thru valgrind where possible
* Add the make check files administrative files to .gitignore
Signed-off-by: Loic Dachary <loic@dachary.org>