libdraw: do not let devdraw fork, for OS X

src/libdraw/drawclient.c

diff --git a/src/libdraw/drawclient.c b/src/libdraw/drawclient.c
index 5e9c950..f3c42b8 100644
--- a/src/libdraw/drawclient.c
+++ b/src/libdraw/drawclient.c
@@ -42,8 +42,12 @@
 		 * The argv0 has no meaning to devdraw.
 		 * Pass it along only so that the various
 		 * devdraws in psu -a can be distinguished.
+		 * The NOLIBTHREADDAEMONIZE keeps devdraw from
+		 * forking before threadmain. OS X hates it when
+		 * guis fork.
 		 */
-		execl("devdraw", argv0, argv0, nil);
+		putenv("NOLIBTHREADDAEMONIZE", "1");
+		execl("devdraw", argv0, argv0, "(devdraw)", nil);
 		sysfatal("exec devdraw: %r");
 	}
 	close(p[1]);