feat(unix): add poll

core/os/os_linux.odin

@@ -432,6 +432,18 @@ AT_FDCWD            :: ~uintptr(99)	/* -100 */
 AT_REMOVEDIR        :: uintptr(0x200)
 AT_SYMLINK_NOFOLLOW :: uintptr(0x100)
 
+pollfd :: struct {
+  fd:      c.int,
+  events:  c.short,
+  revents: c.short,
+}
+
+nfds_t :: distinct c.uint
+
+sigset_t :: struct {
+  __val: [16]c.ulong,
+}
+
 foreign libc {
 	@(link_name="__errno_location") __errno_location    :: proc() -> ^int ---
 
@@ -1087,3 +1099,27 @@ fcntl :: proc(fd: int, cmd: int, arg: int) -> (int, Errno) {
 	}
 	return result, ERROR_NONE
 }
+
+// select :: proc(nfds: int, readfds: ^fd_set, writefds: ^fd_set, exceptfds: ^fd_set, timeout: ^timeval) -> (int, Errno) {
+//   result := unix.sys_select(nfds, readfds, writefds, exceptfds, timeout)
+//   if result < 0 {
+//     return 0, _get_errno(result)
+//   }
+//   return result, ERROR_NONE
+// }
+
+poll :: proc(fds: [^]pollfd, nfds: nfds_t, timeout: int) -> (int, Errno) {
+  result := unix.sys_poll(fds, uint(nfds), timeout)
+  if result < 0 {
+    return 0, _get_errno(result)
+  }
+  return result, ERROR_NONE
+}
+
+ppoll :: proc(fds: [^]pollfd, nfds: nfds_t, timeout: ^unix.timespec, sigmask: ^sigset_t) -> (int, Errno) {
+  result := unix.sys_ppoll(fds, uint(nfds), timeout, sigmask, size_of(sigset_t))
+  if result < 0 {
+    return 0, _get_errno(result)
+  }
+  return result, ERROR_NONE
+}