Move to using -fdiagnostics-color=always on both GCC and Clang

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@229927 91177308-0d34-0410-b5e6-96231b3b80d8

test/libcxx/test/config.py

@@ -479,14 +479,6 @@ class Configuration(object):
         if use_color != '':
             self.lit_config.fatal('Invalid value for color_diagnostics "%s".'
                                   % use_color)
-        cxx_type = self.cxx.type
-        if cxx_type is None:
-            self.lit_config.warning(
-                'Unable to force color output for unknown compiler "%s"'
-                % cxx.path)
-        elif cxx_type in ['clang', 'apple-clang']:
-            self.cxx.flags += ['-fcolor-diagnostics']
-        elif cxx_type == 'gcc':
         self.cxx.flags += ['-fdiagnostics-color=always']
 
     def configure_debug_mode(self):