add support for parsing and emitting .section directives. We can now parse

things like:
.section __TEXT,__cstring,cstring_literals




git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@74058 91177308-0d34-0410-b5e6-96231b3b80d8

tools/llvm-mc/AsmParser.h

@@ -52,6 +52,10 @@ private:
   bool ParseX86InstOperands(MCInst &Inst);
   bool ParseX86Operand(X86Operand &Op);
   bool ParseX86MemOperand(X86Operand &Op);
+  
+  // Directive Parsing.
+  bool ParseDirectiveSection();
+  
 };
 
 } // end namespace llvm