Pass engine name and version parts as proper strings

Removes the need for _MKSTR all over the place which has the drawback of
converting _MKSTR(UNKNOWN_DEFINE) to "UKNOWN_DEFINE" instead of throwing
a compilation error.

platform/android/export/export.cpp

@@ -370,7 +370,7 @@ class EditorExportAndroid : public EditorExportPlatform {
 		}
 
 		if (aname == "") {
-			aname = _MKSTR(VERSION_NAME);
+			aname = VERSION_NAME;
 		}
 
 		return aname;