Add a variable to track whether or not we've used a unique section,

e.g. linkonce, to TargetMachine and set it when we've done so
for ELF targets currently. This involved making TargetMachine
non-const in a TLOF use and propagating that change around - I'm
open to other ideas.

This will be used in a future commit to handle emitting debug
information with ranges.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@199871 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Target/PowerPC/PPCTargetObjectFile.h

@@ -22,9 +22,10 @@ namespace llvm {
 
     virtual void Initialize(MCContext &Ctx, const TargetMachine &TM);
 
-    virtual const MCSection *
-    SelectSectionForGlobal(const GlobalValue *GV, SectionKind Kind,
-                           Mangler *Mang, const TargetMachine &TM) const;
+    virtual const MCSection *SelectSectionForGlobal(const GlobalValue *GV,
+                                                    SectionKind Kind,
+                                                    Mangler *Mang,
+                                                    TargetMachine &TM) const;
 
     /// \brief Describe a TLS variable address within debug info.
     virtual const MCExpr *getDebugThreadLocalSymbol(const MCSymbol *Sym) const;