gollvm: sync with LLVM trunk r336809

Signature for llvm::sys::ExecuteAndWait has changed.

Fixes golang/go#26331.

Change-Id: I67394cbfcb552f4aa251c8ad64ae29c4c9d52cb5
Reviewed-on: https://go-review.googlesource.com/123295
Reviewed-by: Cherry Zhang <cherryyz@google.com>
diff --git a/driver/Command.cpp b/driver/Command.cpp
index e27114b..2f10e8c 100644
--- a/driver/Command.cpp
+++ b/driver/Command.cpp
@@ -31,9 +31,14 @@
 
 int Command::execute(std::string *errMsg)
 {
+  std::vector<llvm::StringRef> argv;
+  size_t n = arguments_.size() - 1;
+  argv.reserve(n);
+  for (size_t i = 0; i < n; ++i)
+    argv.push_back(arguments_[i]);
   return llvm::sys::ExecuteAndWait(executable_,
-                                   arguments_.data(),
-                                   /*env=*/nullptr,
+                                   argv,
+                                   /*env=*/llvm::None,
                                    /*Redirects*/{},
                                    /*secondsToWait=*/0,
                                    /*memoryLimit=*/0,