Now to chant the magical incantation that will exorcise the System library
from LLVM forever:

grep -lR "llvm/System" * | grep -v .svn | xargs sed -ie 's#llvm/System#llvm/Support#g'

llvm-svn: 120314
diff --git a/llvm/lib/Support/Windows/RWMutex.inc b/llvm/lib/Support/Windows/RWMutex.inc
index 82ae8af..471f8fa 100644
--- a/llvm/lib/Support/Windows/RWMutex.inc
+++ b/llvm/lib/Support/Windows/RWMutex.inc
@@ -1,4 +1,4 @@
-//= llvm/System/Win32/Mutex.inc - Win32 Reader/Writer Mutual Exclusion Lock  =//
+//= llvm/Support/Win32/Mutex.inc - Win32 Reader/Writer Mutual Exclusion Lock  =//
 //
 //                     The LLVM Compiler Infrastructure
 //