Put Target definitions inside Target specific header, and llvm namespace.

llvm-svn: 76344
diff --git a/llvm/lib/Target/X86/X86.h b/llvm/lib/Target/X86/X86.h
index 457e18a..0c3bc39 100644
--- a/llvm/lib/Target/X86/X86.h
+++ b/llvm/lib/Target/X86/X86.h
@@ -71,6 +71,8 @@
 ///
 FunctionPass *createX86MaxStackAlignmentCalculatorPass();
 
+extern Target TheX86_32Target, TheX86_64Target;
+
 } // End llvm namespace
 
 // Defines symbolic names for X86 registers.  This defines a mapping from