[mtouch] Move string null/empty check into CompilerFlags.AddOtherFlag. (#6027)

tools/common/CompilerFlags.cs

@@ -101,6 +101,8 @@ namespace Xamarin.Utils
 
 		public void AddOtherFlag (string flag)
 		{
+			if (string.IsNullOrEmpty (flag))
+				return;
 			if (OtherFlags == null)
 				OtherFlags = new HashSet<string> ();
 			OtherFlags.Add (flag);

tools/mtouch/Target.cs

@@ -1137,10 +1137,8 @@ namespace Xamarin.Bundler
 							}
 						}
 					}
-					if (App.Embeddinator) {
-						if (!string.IsNullOrEmpty (App.UserGccFlags))
-							compiler_flags.AddOtherFlag (App.UserGccFlags);
-					}
+					if (App.Embeddinator)
+						compiler_flags.AddOtherFlag (App.UserGccFlags);
 					compiler_flags.LinkWithMono ();
 					compiler_flags.LinkWithXamarin ();
 					if (GetAllSymbols ().Contains ("UIApplicationMain"))
@@ -1558,8 +1556,7 @@ namespace Xamarin.Bundler
 				linker_flags.AddLinkWith (libilgen);
 			}
 
-			if (!string.IsNullOrEmpty (App.UserGccFlags))
-				linker_flags.AddOtherFlag (App.UserGccFlags);
+			linker_flags.AddOtherFlag (App.UserGccFlags);
 
 			if (App.DeadStrip)
 				linker_flags.AddOtherFlag ("-dead_strip");