Typo and missing checkin from r131186.

llvm-svn: 131187
diff --git a/llvm/lib/Support/Windows/Program.inc b/llvm/lib/Support/Windows/Program.inc
index 350363c..b685bb8 100644
--- a/llvm/lib/Support/Windows/Program.inc
+++ b/llvm/lib/Support/Windows/Program.inc
@@ -332,7 +332,8 @@
 int
 Program::Wait(const Path &path,
               unsigned secondsToWait,
-              std::string* ErrMsg) {
+              std::string* ErrMsg,
+              const char* /*SignalPrefix*/) {
   if (Data_ == 0) {
     MakeErrMsg(ErrMsg, "Process not started!");
     return -1;