Remove pledge() support for OpenBSD (#6048)

While this initially worked fine, at some point these patches broke
because libcairo started calling shmget(2) - a syscall not covered by
any pledge promise - and a common pitfall when using pledge with
graphics-oriented applications.

Various attempts were made to fix them, but at some time they were
simply disabled in the OpenBSD port:


openbsd/ports@a4a9f41
openbsd/ports@5a03c38

This seems pointless and creates needless friction both for the i3 team
who was willing to carry ugly code and for the OpenBSD ports maintainers
who had to disable that code again.

Let's abandon this experiment.

i3-msg/main.c

@@ -148,11 +148,6 @@ static yajl_callbacks config_callbacks = {
 };
 
 int main(int argc, char *argv[]) {
-#if defined(__OpenBSD__)
-    if (pledge("stdio rpath unix", NULL) == -1) {
-        err(EXIT_FAILURE, "pledge");
-    }
-#endif
     char *socket_path = NULL;
     int o, option_index = 0;
     uint32_t message_type = I3_IPC_MESSAGE_TYPE_RUN_COMMAND;

i3-nagbar/main.c

@@ -513,12 +513,6 @@ int main(int argc, char *argv[]) {
     font = load_font(pattern, true);
     set_font(&font);
 
-#if defined(__OpenBSD__)
-    if (pledge("stdio rpath wpath cpath getpw proc exec", NULL) == -1) {
-        err(EXIT_FAILURE, "pledge");
-    }
-#endif
-
     /* Default values if we cannot determine the preferred window position. */
     xcb_rectangle_t win_pos = (xcb_rectangle_t){50, 50, 500, font.height + 2 * MSG_PADDING + BAR_BORDER};
     if (position_on_primary) {

src/main.c

@@ -1147,12 +1147,6 @@ int main(int argc, char *argv[]) {
         }
     }
 
-#if defined(__OpenBSD__)
-    if (pledge("stdio rpath wpath cpath proc exec unix", NULL) == -1) {
-        err(EXIT_FAILURE, "pledge");
-    }
-#endif
-
     if (!disable_signalhandler) {
         setup_signal_handler();
     } else {