Don’t loop 65536 FDs, trying to close them, when fork+exec:ing

All FDs should now have the CLOEXEC flag set, and thus there’s no
longer needed to manually loop “all” possible FDs and (trying to)
close them.

Note: the alsa module (alsalib, actually) is “racy” - while booting
up, it temporarily opens the asoundrc file without CLOEXEC. If
e.g. the script module starts its script inside this window, it’ll
have a leaked FD. Not much we can do about it though :/

Closes #169

particle.c

@@ -277,11 +277,6 @@ exposable_default_on_mouse(struct exposable *exposable, struct bar *bar,
                     goto fail;
                 }
 
-                /* Close *all* other FDs (e.g. script modules' FDs) */
-                for (int i = STDERR_FILENO + 1; i < 65536; i++)
-                    if (i != pipe_fds[1])
-                        close(i);
-
                 execvp(argv[0], argv);
 
             fail: