move elf section uniquing to MCContext.  Along the way
merge XCore's section into MCSectionELF

llvm-svn: 100812
diff --git a/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp b/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
index 37687d2..63f865d 100644
--- a/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
@@ -705,7 +705,7 @@
   // to be executable. Some targets have a directive to declare this.
   Function *InitTrampolineIntrinsic = M.getFunction("llvm.init.trampoline");
   if (!InitTrampolineIntrinsic || InitTrampolineIntrinsic->use_empty())
-    if (MCSection *S = MAI->getNonexecutableStackSection(OutContext))
+    if (const MCSection *S = MAI->getNonexecutableStackSection(OutContext))
       OutStreamer.SwitchSection(S);
   
   // Allow the target to emit any magic that it wants at the end of the file,