Freeciv

Note: This patch puts simplicity of the generation code over simplicity of the generated code, producing clunky-looking code for simple fields, like

 e = 0;
 e |= DIO_PUT(...);
 if (e) {
   log_packet_detailed("... field error detected");
 }

instead of the simpler

 if (DIO_PUT(...)) {
   log_packet_detailed("... field error detected");
 }

This will be a trend in further patches – the advantage being that the e |= DIO_PUT(...); line can be reused in other places (such as for array elements) in the future, and the surrounding code works equally well for less-simple fields (i.e. arrays).