linux-user: avoid treading on gprof's SIGPROF signals

The guest tends to get confused when it receives signals it doesn't
know about. Given the gprof magic has also set up it's own handler we
would do well to avoid stomping on it as well.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20190502145846.26226-1-alex.bennee@linaro.org>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>

linux-user/signal.c

@@ -508,6 +508,11 @@ void signal_init(void)
     act.sa_flags = SA_SIGINFO;
     act.sa_sigaction = host_signal_handler;
     for(i = 1; i <= TARGET_NSIG; i++) {
+#ifdef TARGET_GPROF
+        if (i == SIGPROF) {
+            continue;
+        }
+#endif
         host_sig = target_to_host_signal(i);
         sigaction(host_sig, NULL, &oact);
         if (oact.sa_sigaction == (void *)SIG_IGN) {