maint: targets and recipes to simplify testing on real-world packages We introduce a new section in the maintainer-specific makefile that contains recipes to test the build system of some well-known GNU packages with the current development version of Automake. Not the cleanest way to do so, but good enough for the moment. We'll revisit the matter after the 1.13.2 release (which we now hope will happen soon). * maint.mk (git-sv-host): New. (SV_GIT_CF, SV_GIT_AC, SV_GIT_GL): Use it to reduce code duplication. (ALL_PACKAGES, FEW_PACKAGES): New, lists of GNU packages to try out. (ttp-check, ttp-check-all): New targets, do the checking with said packages. (ttp): New, alias for 'ttp-check'. (ttp-all): New, alias for 'ttp-check-all'. Signed-off-by: Stefano Lattarini <stefano.lattarini@gmail.com>