Here's my temporary workaround, which I injected into my copy of eval.c:
Code
#define PAUSE_RESUME ".\\_pause_.txt"
#ifdef PAUSE_RESUME
void pauseLoop() {
	if (Live)return;
	if (!file_length(PAUSE_RESUME)) return;
	print(TO_ANY, "\nJobs are PAUSED.");
	while (wait(0) && file_length(PAUSE_RESUME)) {
		if (msg("Resume Jobs?")) { file_delete(PAUSE_RESUME); break; };
	}
	print(TO_ANY, "\nJobs have RESUMED.");
}
#endif
DLLFUNC void evaluate()
{
#ifdef PAUSE_RESUME
	pauseLoop();
#endif

To pause, all I need to do is to make a file "_pause_.txt" in the Zorro folder with a nonzero number of characters in the body.