STORM-1182 FIX Fixed XUI Preview tool not loading XML files from a dev checkout on Mac.

Ported Vadim's STORM-1182 fix for Linux (3d30b2bc1369) to the
corresponding Mac file.

doc/contributions.txt

@@ -204,6 +204,7 @@ Boroondas Gupte
 	SNOW-624
 	SNOW-737
 	STORM-318
+	STORM-1182
 	VWR-233
 	VWR-20583
 	VWR-20891

indra/llvfs/lldir_mac.cpp

@@ -150,11 +150,11 @@ LLDir_Mac::LLDir_Mac()
 		CFURLRef resourcesURLRef = CFBundleCopyResourcesDirectoryURL(mainBundleRef);
 		CFURLRefToLLString(resourcesURLRef, mAppRODataDir, true);
 		
-		U32 indra_pos = mExecutableDir.find("/indra");
-		if (indra_pos != std::string::npos)
+		U32 build_dir_pos = mExecutableDir.find("/build-darwin-");
+		if (build_dir_pos != std::string::npos)
 		{
 			// ...we're in a dev checkout
-			mSkinBaseDir = mExecutableDir.substr(0, indra_pos)
+			mSkinBaseDir = mExecutableDir.substr(0, build_dir_pos)
 				+ "/indra/newview/skins";
 			llinfos << "Running in dev checkout with mSkinBaseDir "
 				<< mSkinBaseDir << llendl;