NFC: Ignore deprecation of asl_log in SourceKit.

ASL is deprecated in macOS 10.12. It may be time to transition to os_log now
that deployment targets have been raised to 10.12, but until that project
starts these warnings are just pollution.

Filed rdar://121076739 to track adoption of `os_log()` if appropriate.

tools/SourceKit/lib/Support/Logging.cpp

@@ -66,6 +66,9 @@ Logger::~Logger() {
   fprintf(stderr, "%s: %s\n", LoggerName.c_str(), LogMsg.c_str());
 
 #if __APPLE__
+  // rdar://121076739
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wdeprecated-declarations"
   // Use the Apple System Log facility.
   aslclient asl = asl_open(LoggerName.c_str(), "com.apple.console",
                            ASL_OPT_NO_DELAY);
@@ -76,5 +79,6 @@ Logger::~Logger() {
   asl_send(asl, msg);
   asl_free(msg);
   asl_close(asl);
+#pragma clang diagnostic pop
 #endif
 }