error_with_pos
error_with_pos("redefinition of %s", name);
error_with_pos("expand undefined %s %s",
error_with_pos("export undefined symbol %s", name);
void error_with_pos(const char *, ...) __attribute__ ((format(printf, 1, 2)));
error_with_pos("unexpected second declaration name");
error_with_pos("%s", e);