"Mac OS/X" -> "Mac OS X" spelling fixes for llvm.

Patch from Sean McBride <sean@rogue-research.com>!

llvm-svn: 203258
diff --git a/llvm/lib/Target/TargetLibraryInfo.cpp b/llvm/lib/Target/TargetLibraryInfo.cpp
index 46cce84..0631516 100644
--- a/llvm/lib/Target/TargetLibraryInfo.cpp
+++ b/llvm/lib/Target/TargetLibraryInfo.cpp
@@ -379,7 +379,7 @@
   }
 #endif // !NDEBUG
   
-  // memset_pattern16 is only available on iOS 3.0 and Mac OS/X 10.5 and later.
+  // memset_pattern16 is only available on iOS 3.0 and Mac OS X 10.5 and later.
   if (T.isMacOSX()) {
     if (T.isMacOSXVersionLT(10, 5))
       TLI.setUnavailable(LibFunc::memset_pattern16);