gollvm: accept -fsplit-stack on the command line

Accept the -fsplit-stack command line option (oddly, this one
somehow never made it into the list when the command line
flag handling was transitioned to llvm::opt and friends).

Change-Id: Ib2919d1d33c1f2b7e37d245fa4039d24b9031514
Reviewed-on: https://go-review.googlesource.com/112366
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
diff --git a/driver/GollvmOptions.td b/driver/GollvmOptions.td
index 869a3aa..9b049d3 100644
--- a/driver/GollvmOptions.td
+++ b/driver/GollvmOptions.td
@@ -213,6 +213,8 @@
 // Target-independent "-f" options.
+def fsplit_stack : Flag<["-"], "fsplit-stack">, Group<f_Group>;
 def fPIC : Flag<["-"], "fPIC">, Group<f_Group>;
 def fno_PIC : Flag<["-"], "fno-PIC">, Group<f_Group>;
 def fpic : Flag<["-"], "fpic">, Group<f_Group>;