Fixes issue 29539 with the workaround of initializing libnotify early by calling localtime_r in OS:…

runtime/vm/os_macos.cc

Index: runtime/vm/os_macos.cc
diff --git a/runtime/vm/os_macos.cc b/runtime/vm/os_macos.cc
index d4ff67912c6b0b7b1697b730a9d6f83e3cdfdc6a..9e9241c67746bde19227db25e31fb843702c3d2e 100644
--- a/runtime/vm/os_macos.cc
+++ b/runtime/vm/os_macos.cc
@@ -423,6 +423,21 @@ void OS::InitOnce() {
   static bool init_once_called = false;
   ASSERT(init_once_called == false);
   init_once_called = true;
+
+  // See https://github.com/dart-lang/sdk/issues/29539
+  // This is a workaround for a macos bug, we eagerly call localtime_r so that
+  // libnotify is initialized early before any fork happens.
+  struct timeval tv;
+  if (gettimeofday(&tv, NULL) < 0) {
+    FATAL1("gettimeofday returned an error (%s)\n", strerror(errno));
+    return;
+  }
+  tm decomposed;
+  struct tm* error_code = localtime_r(&(tv.tv_sec), &decomposed);
+  if (error_code == NULL) {
+    FATAL1("localtime_r returned an error (%s)\n", strerror(errno));
+    return;
+  }
 }