* tests/subobj3.test: Exit with status 77 if gcc not found.

	* tests/subobj3.test: Exit with status 77 if gcc not found.
	* tests/pr9.test: Exit with status 77 if gzip not found.
	* tests/pr87.test: Exit with status 77 if gcc not found.
	* tests/pr19.test: Exit with status 77 if gzip or gcc not found.
	* tests/install2.test: Exit with status 77 if gzip not found.
	* tests/exsource.test: Exit with status 77 if GNU make not found.
	* tests/ansi3.test: Exit with status 77 if gcc not found.

	* tests/target-cflags.test: Require GNU make.  Exit with status 77
	if gcc or make not found.  Fixes PR automake/121.