simple libc tests

based on the libc-testsuit of dalias

see http://git.musl-libc.org/cgit

build tests:

	cp dist/config.mak .

	# edit config.mak

	make

run tests:

	make run

framework:

the convention is that each test is in a separate file

at a path like src/directory/file.c with its own main

the test should return 0 on success and non-0 on failure