Used the TypeScript getCanonicalFileName

Author: cartant

lib/Host.js

@@ -113,7 +113,7 @@ module.exports = function (ts) {
 	};
 
 	Host.prototype.getCanonicalFileName = function (filename) {
-		return this._normalizedRelative(filename);
+		return ts.sys.useCaseSensitiveFileNames ? filename : filename.toLowerCase();
 	};
 
 	Host.prototype.useCaseSensitiveFileNames = function () {