Remove the Darwin_Generic_GCC toolchain.

This is currently unused by any test. The code path would still be hit
by clang on ppc, but

* PPC has not been supported on current versions of OS X
* A port of current clang to older OS X on ppc should be using
toolchains::DarwinClang.

llvm-svn: 195585
diff --git a/clang/lib/Driver/Driver.cpp b/clang/lib/Driver/Driver.cpp
index 5307910..8cfaa6c 100644
--- a/clang/lib/Driver/Driver.cpp
+++ b/clang/lib/Driver/Driver.cpp
@@ -1926,13 +1926,7 @@
     case llvm::Triple::Darwin:
     case llvm::Triple::MacOSX:
     case llvm::Triple::IOS:
-      if (Target.getArch() == llvm::Triple::x86 ||
-          Target.getArch() == llvm::Triple::x86_64 ||
-          Target.getArch() == llvm::Triple::arm ||
-          Target.getArch() == llvm::Triple::thumb)
-        TC = new toolchains::DarwinClang(*this, Target, Args);
-      else
-        TC = new toolchains::Darwin_Generic_GCC(*this, Target, Args);
+      TC = new toolchains::DarwinClang(*this, Target, Args);
       break;
     case llvm::Triple::DragonFly:
       TC = new toolchains::DragonFly(*this, Target, Args);