osdep: remove erroneous POLLERR emulation

first of all, POLLERR is supposed to be ignored in `.events` and only
returned in `.revents`.

secondly select()'s exceptfds does not have a 1:1 correspondence with
POLLERR. thankfully, the only caller of this function (in terminal-unix)
never set the POLLERR flag so the errorfds were unused anyways.

so go ahead and remove it entirely instead of pretending we can emulate
something that's not possible.

2 files changed, 3 insertions, 10 deletions

diff --git a/osdep/polldev.c b/osdep/polldev.c
index ba2df2a2e3..dc86d5d022 100644
--- a/osdep/polldev.c
+++ b/osdep/polldev.c
@@ -27,10 +27,9 @@
 int polldev(struct pollfd fds[], nfds_t nfds, int timeout) {
 #ifdef __APPLE__
     int maxfd = 0;
-    fd_set readfds, writefds, errorfds;
+    fd_set readfds, writefds;
     FD_ZERO(&readfds);
     FD_ZERO(&writefds);
-    FD_ZERO(&errorfds);
     for (size_t i = 0; i < nfds; ++i) {
         struct pollfd *fd = &fds[i];
         if (fd->fd > maxfd) {
@@ -42,15 +41,12 @@ int polldev(struct pollfd fds[], nfds_t nfds, int timeout) {
         if ((fd->events & POLLOUT)) {
             FD_SET(fd->fd, &writefds);
         }
-        if ((fd->events & POLLERR)) {
-            FD_SET(fd->fd, &errorfds);
-        }
     }
     struct timeval _timeout = {
         .tv_sec = timeout / 1000,
         .tv_usec = (timeout % 1000) * 1000
     };
-    int n = select(maxfd + 1, &readfds, &writefds, &errorfds,
+    int n = select(maxfd + 1, &readfds, &writefds, NULL,
         timeout != -1 ? &_timeout : NULL);
     if (n < 0) {
         return n;
@@ -64,9 +60,6 @@ int polldev(struct pollfd fds[], nfds_t nfds, int timeout) {
         if (FD_ISSET(fd->fd, &writefds)) {
             fd->revents |= POLLOUT;
         }
-        if (FD_ISSET(fd->fd, &errorfds)) {
-            fd->revents |= POLLERR;
-        }
     }
     return n;
 #else
diff --git a/osdep/polldev.h b/osdep/polldev.h
index 50b6db29bc..8593c1e77c 100644
--- a/osdep/polldev.h
+++ b/osdep/polldev.h
@@ -3,5 +3,5 @@
 #include <poll.h>
 
 // Behaves like poll(3) but works for device files on macOS.
-// Only supports POLLIN, POLLOUT, and POLLERR.
+// Only supports POLLIN and POLLOUT.
 int polldev(struct pollfd fds[], nfds_t nfds, int timeout);