Before this change, this command:
```
valgrind --log-file=valgrind.log tmux -f /dev/null start-server \; run true \; kill-server
```
Gave these errors:
```
==3477== Conditional jump or move depends on uninitialised value(s)
==3477== at 0x484E5BE: strlcpy (in /usr/libexec/valgrind/vgpreload_memcheck-amd64-linux.so)
==3477== by 0x167D28: job_run (job.c:193)
==3477== by 0x14002D: cmd_run_shell_timer (cmd-run-shell.c:196)
==3477== by 0x48B724D: ??? (in /usr/lib/x86_64-linux-gnu/libevent_core-2.1.so.7.0.1)
==3477== by 0x48B793E: event_base_loop (in /usr/lib/x86_64-linux-gnu/libevent_core-2.1.so.7.0.1)
==3477== by 0x17A766: proc_loop (proc.c:213)
==3477== by 0x18EEF3: server_start (server.c:253)
==3477== by 0x12D872: client_connect (client.c:164)
==3477== by 0x12D872: client_main (client.c:295)
==3477== by 0x128307: main (tmux.c:537)
==3477==
==3477== Conditional jump or move depends on uninitialised value(s)
==3477== at 0x484E677: strlcpy (in /usr/libexec/valgrind/vgpreload_memcheck-amd64-linux.so)
==3477== by 0x167D28: job_run (job.c:193)
==3477== by 0x14002D: cmd_run_shell_timer (cmd-run-shell.c:196)
==3477== by 0x48B724D: ??? (in /usr/lib/x86_64-linux-gnu/libevent_core-2.1.so.7.0.1)
==3477== by 0x48B793E: event_base_loop (in /usr/lib/x86_64-linux-gnu/libevent_core-2.1.so.7.0.1)
==3477== by 0x17A766: proc_loop (proc.c:213)
==3477== by 0x18EEF3: server_start (server.c:253)
==3477== by 0x12D872: client_connect (client.c:164)
==3477== by 0x12D872: client_main (client.c:295)
==3477== by 0x128307: main (tmux.c:537)
```
Addresses #4421
3rd (variadic) mode_t parameter is irrelevant. Many developers in the past
have passed mode_t (0, 044, 0644, or such), which might lead future people
to copy this broken idiom, and perhaps even believe this parameter has some
meaning or implication or application. Delete them all.
This comes out of a conversation where tb@ noticed that a strange (but
intentional) pledge behaviour is to always knock-out high-bits from
mode_t on a number of system calls as a safety factor, and his bewilderment
that this appeared to be happening against valid modes (at least visually),
but no sorry, they are all irrelevant junk. They could all be 0xdeafbeef.
ok millert
(which does not have many practical uses) and only support running a
program in the popup. display-popup is now simpler and can accept
multiple arguments to avoid escaping problems (like the other commands).
value < 0. errno is only updated in this case. Change all (most?)
callers of syscalls to follow this better, and let's see if this strictness
helps us in the future.
event_reinit) - if the child gets a signal and fires the libevent signal
handler during this period it could write a signal into the parent's
signal pipe. GitHub issue 1001 from Aaron van Geffen.
