make all Emit*() functions consult the TargetLibraryInfo information before creating a call to a library function.
Update all clients to pass the TLI information around.
Previous draft reviewed by Eli.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@160733 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/TargetLibraryInfo.cpp b/lib/Target/TargetLibraryInfo.cpp
index e0a4ecc..7e9cf12 100644
--- a/lib/Target/TargetLibraryInfo.cpp
+++ b/lib/Target/TargetLibraryInfo.cpp
@@ -133,7 +133,8 @@
     "__cxa_atexit",
     "__cxa_guard_abort",
     "__cxa_guard_acquire",
-    "__cxa_guard_release"
+    "__cxa_guard_release",
+    "__memcpy_chk"
   };
 
 /// initialize - Initialize the set of available library functions based on the