Ignore NaCl st_blksize of 0 and buffer writes to raw_fd_ostream.

src/main.cpp

Index: src/main.cpp
diff --git a/src/main.cpp b/src/main.cpp
index eddb94e256d45fc07049ddf0db5b69ae0a907ae2..4763f3ebcbd1ab52f53198dd1724835ad09a4444 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -340,6 +340,9 @@ int main(int argc, char **argv) {
     std::error_code EC;
     raw_fd_ostream *FdOs =
         new raw_fd_ostream(OutputFilename, EC, sys::fs::F_None);
+    // NaCl sets st_blksize to 0, and LLVM uses that to pick the
+    // default preferred buffer size. Set to something non-zero.
+    FdOs->SetBufferSize(1 << 14);
     Os.reset(FdOs);
     if (EC) {
       *Ls << "Failed to open output file: " << OutputFilename << ":\n"