Targets/Darwin: mcount name on Darwin needs to be unmangled.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@126152 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Basic/Targets.cpp b/lib/Basic/Targets.cpp
index a8198e4..55321f2 100644
--- a/lib/Basic/Targets.cpp
+++ b/lib/Basic/Targets.cpp
@@ -152,6 +152,7 @@
   DarwinTargetInfo(const std::string& triple) :
     OSTargetInfo<Target>(triple) {
       this->TLSSupported = llvm::Triple(triple).getDarwinMajorNumber() > 10;
+      this->MCountName = "\01mcount";
     }
 
   virtual std::string isValidSectionSpecifier(llvm::StringRef SR) const {