Fix some failures in targets on available_externally functions,
this fixes a crash on CodeGen/Generic/externally_available.ll
on ppc hosts.  Thanks to Nicholas L for pointing this out.

llvm-svn: 69333
diff --git a/llvm/lib/Target/MSIL/MSILWriter.cpp b/llvm/lib/Target/MSIL/MSILWriter.cpp
index 077145b..6b572f3 100644
--- a/llvm/lib/Target/MSIL/MSILWriter.cpp
+++ b/llvm/lib/Target/MSIL/MSILWriter.cpp
@@ -93,6 +93,12 @@
 
 bool MSILWriter::runOnFunction(Function &F) {
   if (F.isDeclaration()) return false;
+
+  // Do not codegen any 'available_externally' functions at all, they have
+  // definitions outside the translation unit.
+  if (F.hasAvailableExternallyLinkage())
+    return false;
+
   LInfo = &getAnalysis<LoopInfo>();
   printFunction(F);
   return false;