Begin incorporating Python unit tests into build

We now build a separate APE binary for each test so they can run in
parallel. We've got 148 tests running fast and stable so far.

third_party/python/Lib/signal.py

@@ -77,3 +77,50 @@ if 'sigwait' in _globals:
     sigwait.__doc__ = _signal.sigwait
 
 del _globals, _wraps
+
+if __name__ == 'PYOBJ.COM':
+    ITIMER_PROF = 0
+    ITIMER_REAL = 0
+    ITIMER_VIRTUAL = 0
+    NSIG = 0
+    SIGABRT = 0
+    SIGALRM = 0
+    SIGBUS = 0
+    SIGCHLD = 0
+    SIGCONT = 0
+    SIGEMT = 0
+    SIGFPE = 0
+    SIGHUP = 0
+    SIGILL = 0
+    SIGINFO = 0
+    SIGINT = 0
+    SIGIO = 0
+    SIGIOT = 0
+    SIGKILL = 0
+    SIGPIPE = 0
+    SIGPOLL = 0
+    SIGPROF = 0
+    SIGPWR = 0
+    SIGQUIT = 0
+    SIGRTMAX = 0
+    SIGRTMIN = 0
+    SIGSEGV = 0
+    SIGSTOP = 0
+    SIGSYS = 0
+    SIGTERM = 0
+    SIGTRAP = 0
+    SIGTSTP = 0
+    SIGTTIN = 0
+    SIGTTOU = 0
+    SIGURG = 0
+    SIGUSR1 = 0
+    SIGUSR2 = 0
+    SIGVTALRM = 0
+    SIGWINCH = 0
+    SIGXCPU = 0
+    SIGXFSZ = 0
+    SIG_BLOCK = 0
+    SIG_DFL = 0
+    SIG_IGN = 0
+    SIG_SETMASK = 0
+    SIG_UNBLOCK = 0