Almost all tests are initially disabled via the list in Makefile.cfg.
* Makefile.am (EXTRA_DIST): Add .x-sc_avoid_if_before_free.
Omit names of files that automake includes automatically.
* .x-sc_avoid_if_before_free: New file.
* build-aux/vc-list-files: Likewise.
* build-aux/find-unnecessary-if-before-free: Likewise.
* GNUmakefile, Makefile.cfg, Makefile.maint: New files.
