Include errno.h to fix compile errors in gcc 3.4

sim/main.cc:
    Include errno.h

--HG--
extra : convert_revision : ff91579ae590b3c1d11f7468b71f295e6f3edd68

sim/main.cc

@@ -31,6 +31,7 @@
 ///
 #include <sys/types.h>
 #include <sys/stat.h>
+#include <errno.h>
 #include <libgen.h>
 #include <stdlib.h>
 #include <signal.h>