build: avoid parallel distcheck failure

build: avoid parallel distcheck failure

* Makefile.am (ALL_RECURSIVE_TARGETS): Initialize here, too,
to please automake.  Add install-root, check-root, distcheck-hook.
* cfg.mk (ALL_RECURSIVE_TARGETS): Add sc_tight_scope.
* maint.mk (ALL_RECURSIVE_TARGETS): Add patch-check,
check-AUTHORS, maintainer-distcheck, vc-dist, taint-distcheck,
my-distcheck, alpha, beta, major.