Merge revision 21321 to trunk. Fixes issue 8930

dart/runtime/platform/globals.h

Index: dart/runtime/platform/globals.h
===================================================================
--- dart/runtime/platform/globals.h	(revision 21336)
+++ dart/runtime/platform/globals.h	(working copy)
@@ -396,6 +396,36 @@
 }
 
 
+// Some platforms do not support strndup. We add it below as necessary.
+#if defined(TARGET_OS_MACOS)
+// strndup has only been added to Mac OS X in 10.7. We are supplying
+// our own copy here.
+#if !defined(__ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__) || \
+    __ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__ <= 1060
+#define NEEDS_STRNDUP 1
+#endif  // !defined(__ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__)
+#elif defined(TARGET_OS_WINDOWS)
+#define NEEDS_STRNDUP 1
+#endif  // defined(TARGET_OS_MACOS)
+
+#if defined(NEEDS_STRNDUP)
+// size_t used to match function signature on other platforms.
+inline char* strndup(const char* s, size_t n) {
+  size_t len = strlen(s);
+  if (n < len) {
+    len = n;
+  }
+  char* result = reinterpret_cast<char*>(malloc(len + 1));
+  if (!result) {
+    return NULL;
+  }
+  result[len] = '\0';
+  return reinterpret_cast<char*>(memcpy(result, s, len));
+}
+#endif  // defined(NEEDS_STRNDUP)
+#undef NEEDS_STRNDUP
+
+
 // A macro to ensure that memcpy cannot be called. memcpy does not handle
 // overlapping memory regions. Even though this is well documented it seems
 // to be used in error quite often. To avoid problems we disallow the direct