tests: Allow use of random.c under Windows.
* tests/Makefile.am (TESTS): Always include random.c * tests/random.c [!W32]: Include sys/wait.h. (inf): New. (check_forking, check_nonce_forking): Print a notice what will be done. (main) [W32]: Do not call signal.
This change help to run future tests under Windows. The current two
tests are not applicable to Windows.