Support for the mno-stack-arg-probe flag

Adds support for this flag. There is also another piece for llvm
(separate review). More info:
https://bugs.llvm.org/show_bug.cgi?id=36221

By Ruslan Nikolaev!

Differential Revision: https://reviews.llvm.org/D43108

llvm-svn: 325901
diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp
index 5be02c9..956c333 100644
--- a/clang/lib/Frontend/CompilerInvocation.cpp
+++ b/clang/lib/Frontend/CompilerInvocation.cpp
@@ -923,6 +923,8 @@
     Opts.StackProbeSize = StackProbeSize;
   }
 
+  Opts.NoStackArgProbe = Args.hasArg(OPT_mno_stack_arg_probe);
+
   if (Arg *A = Args.getLastArg(OPT_fobjc_dispatch_method_EQ)) {
     StringRef Name = A->getValue();
     unsigned Method = llvm::StringSwitch<unsigned>(Name)