[compiler-rt][profile] Exclude signal.h on WASI

WASI doesn't support signal, so we should exclude signal.h on WASI.
This patch is only for the swiftlang fork of compiler-rt because those
signal usages don't exist in the upstream.

compiler-rt/lib/profile/InstrProfilingFile.c

@@ -13,7 +13,9 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#if !defined(__wasi__)
 #include <signal.h>
+#endif
 #ifdef _MSC_VER
 /* For _alloca. */
 #include <malloc.h>

compiler-rt/lib/profile/InstrProfilingUtil.c

@@ -25,7 +25,9 @@
 #include <sys/utsname.h>
 #endif
 
+#if !defined(__wasi__)
 #include <signal.h>
+#endif
 #include <stdlib.h>
 #include <string.h>
 
@@ -336,6 +338,8 @@ COMPILER_RT_VISIBILITY void lprofInstallSignalHandler(int sig,
   if (err == SIG_ERR)
     PROF_WARN("Unable to install an exit signal handler for %d (errno = %d).\n",
               sig, errno);
+#elif defined(__wasi__)
+  // WASI doesn't support signal.
 #else
   struct sigaction sigact;
   memset(&sigact, 0, sizeof(sigact));