Bring back r250262: PS4 toolchain

There was a minor problem with a test. Sorry for the noise yesterday.

This patch adds missing pieces to clang, including the PS4 toolchain
definition, added warnings, PS4 defaults, and Driver changes needed for
our compiler.

A patch by Filipe Cabecinhas, Pierre Gousseau and Katya Romanova!

Differential Revision: http://reviews.llvm.org/D13482

llvm-svn: 250293
diff --git a/clang/lib/Driver/Driver.cpp b/clang/lib/Driver/Driver.cpp
index dc95ed2..0b842cd 100644
--- a/clang/lib/Driver/Driver.cpp
+++ b/clang/lib/Driver/Driver.cpp
@@ -2261,6 +2261,9 @@
     case llvm::Triple::CUDA:
       TC = new toolchains::CudaToolChain(*this, Target, Args);
       break;
+    case llvm::Triple::PS4:
+      TC = new toolchains::PS4CPU(*this, Target, Args);
+      break;
     default:
       // Of these targets, Hexagon is the only one that might have
       // an OS of Linux, in which case it got handled above already.