Add c++ to "inferlanguage"

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@47185 91177308-0d34-0410-b5e6-96231b3b80d8

utils/ccc

@@ -54,6 +54,8 @@ def changeextension(path, newext):
 def inferlanguage(extension):
     if extension == "c":
         return "c"
+    elif extension in ["cpp", "cc"]:
+        return "c++"
     elif extension == "i":
         return "c-cpp-output"
     elif extension == "m":