standardise --enable-installed-tests
Submitted by Allison (desrt)
Link to original bug (#701241)
Description
I have a branch that aims to standardise the handling of installed tests across all modules by way of introducing a new m4 macro and expanding Makefile.decl.
This new functionality facilitates a substantial cleanup of glib's Makefiles.
The m4 macro isn't installed yet. I'd rather keep this on a copy-paste basis for now (as is already the case with Makefile.decl).
Please see https://git.gnome.org/browse/glib/log/?h=wip/test-cleanup