* winsup.h (flush_file_buffers): Declare new function.

(FLushFileBuffers): New define.
	* miscfuncs.cc (flush_file_buffers): Define new function.

winsup/cygwin/miscfuncs.cc

@@ -361,3 +361,14 @@ create_pipe (PHANDLE hr,PHANDLE hw, LPSECURITY_ATTRIBUTES sa, DWORD n)
       break;
   return false;
 }
+
+#undef FlushFileBuffers
+bool
+flush_file_buffers (HANDLE h)
+{
+  DWORD ftype = GetFileType (h);
+  /* Per MSDN, FlushFileBuffers on named pipes might block.  This is the last
+     we want it to do, especially when printing debug output  as when calling
+     system_printf. */
+  return (ftype != FILE_TYPE_PIPE) ? FlushFileBuffers (h) : true;
+}