timerfd_create is Linux-specific; this patch uses only POSIX functions
and has been tested on Linux and OpenBSD.
Also make processEvent return 1 to tell us when to quit.
---
 src/uxn11.c | 93 +++++++++++++++++++++++++++++++++++++++--------------
 1 file changed, 68 insertions(+), 25 deletions(-)

diff --git a/src/uxn11.c b/src/uxn11.c
index 3142ddf..5b7e76e 100644
--- a/src/uxn11.c
+++ b/src/uxn11.c
@@ -1,10 +1,12 @@
+#define _POSIX_C_SOURCE 199309L
+#include <poll.h>
+#include <signal.h>
 #include <stdio.h>
 #include <stdlib.h>
+#include <time.h>
+#include <unistd.h>
 #include <X11/Xlib.h>
 #include <X11/Xutil.h>
-#include <sys/timerfd.h>
-#include <unistd.h>
-#include <poll.h>
 
 #include "uxn.h"
 #include "devices/system.h"
@@ -117,7 +119,7 @@ hide_cursor(void)
 #define XK_Control 0xffe3
 #define XK_Alt 0xffe9
 
-static void
+static int
 processEvent(void)
 {
 	XEvent ev;
@@ -130,7 +132,7 @@ processEvent(void)
 		XDestroyImage(ximage);
 		XDestroyWindow(display, window);
 		XCloseDisplay(display);
-		exit(0);
+		return 1;
 	} break;
 	case KeyPress: {
 		XKeyPressedEvent *e = (XKeyPressedEvent *)&ev;
@@ -171,6 +173,7 @@ processEvent(void)
 		mouse_pos(devmouse, e->x, e->y);
 	} break;
 	}
+	return 0;
 }
 
 static int
@@ -220,14 +223,53 @@ init(void)
 	return 1;
 }
 
+static void
+timer_loop(int fd)
+{
+	struct timespec s;
+	s.tv_sec = 0;
+	s.tv_nsec = 16666667; /* 1/60 s in ns */
+	while (1) {
+		write(fd, "", 1);
+		nanosleep(&s, NULL);
+	}
+}
+
+static void
+main_loop(int fd, Uxn *u)
+{
+	int pollret;
+	struct pollfd fds[2];
+	fds[0].fd = ConnectionNumber(display);
+	fds[1].fd = fd;
+	fds[0].events = fds[1].events = POLLIN;
+
+	/* main loop */
+	while(1) {
+		fds[0].revents = fds[1].revents = 0;
+		pollret = poll(fds, 2, -1);
+		if (pollret <= 0)
+			continue;
+		while(XPending(display))
+			if (processEvent() != 0)
+				return;
+		if (fds[1].revents) {
+			char discard;
+			uxn_eval(u, GETVECTOR(devscreen));
+			read(fds[1].fd, &discard, 1);
+		}
+		if(uxn_screen.fg.changed || uxn_screen.bg.changed)
+			redraw();
+	}
+}
+
 int
 main(int argc, char **argv)
 {
 	Uxn u;
 	int i;
-	char expirations[8];
-	struct pollfd fds[2];
-	static const struct itimerspec screen_tspec = {{0, 16666666}, {0, 16666666}};
+	int pipes[2];
+	pid_t pid;
 	if(argc < 2)
 		return error("Usage", "uxncli game.rom args");
 	if(!start(&u, argv[1]))
@@ -240,23 +282,24 @@ main(int argc, char **argv)
 		while(*p) console_input(&u, *p++);
 		console_input(&u, '\n');
 	}
-	fds[0].fd = XConnectionNumber(display);
-	fds[1].fd = timerfd_create(CLOCK_MONOTONIC, 0);
-	timerfd_settime(fds[1].fd, 0, &screen_tspec, NULL);
-	fds[0].events = fds[1].events = POLLIN;
-	/* main loop */
-	while(1) {
-		if(poll(fds, 2, 1000) <= 0)
-			continue;
-		while(XPending(display))
-			processEvent();
-		if(poll(&fds[1], 1, 0)) {
-			read(fds[1].fd, expirations, 8);    /* Indicate we handled the timer */
-			uxn_eval(&u, GETVECTOR(devscreen)); /* Call the vector once, even if the timer fired multiple times */
-		}
-		if(uxn_screen.fg.changed || uxn_screen.bg.changed)
-			redraw();
+
+	if (pipe(pipes) != 0)
+		return error("Pipe", "Failed");
+
+	pid = fork();
+	if (pid == -1) {
+		return error("Fork", "Failed");
+	} else if (pid == 0) {
+		/* child */
+		close(pipes[0]);
+		timer_loop(pipes[1]);
+	} else {
+		/* parent */
+		close(pipes[1]);
+		main_loop(pipes[0], &u);
+
+		free(u.ram);
+		kill(pid, SIGKILL);
 	}
-	XDestroyImage(ximage);
 	return 0;
 }
-- 
2.35.1