swift234

[PrintAsObjC] Avoid using C/C++ keywords in methods and properties.

This very simply avoids printing properties and method arguments whose
names match /any/ keyword recognized by Clang, in any language mode.
That's a bit overkill, but it's easiest to implement. If someone /does/
name their property or argument using a keyword, a single underscore is
appended. That's suboptimal for properties, but better than the "header
fails to parse" alternative.

If you've named your /type/ something that conflicts with C, you deserve
what you get. Mark the thing @nonobjc. (We could actually check this in
Sema, but it's rare enough that I'm going to punt on doing that for now.)

rdar://problem/21060399

Swift SVN r29473