[PATCH] Improved error recovery for _Pragma

[Rachel Craik]

With the proposed patch, the first case is handled exactly the same as the current trunk. In regards to the second case, a `BalancedDelimiterTracker` //could // (in theory) be used instead to eat all tokens until the closing ')', if it exists. However, `_Pragma` is handled by the preprocessor, and I believe `BalancedDelimiterTracker` can only used from within the parser.

With this patch I have tried to follow the style used elsewhere in the preprocessor.


http://reviews.llvm.org/D8308

EMAIL PREFERENCES
  http://reviews.llvm.org/settings/panel/emailpreferences/