Isn't
"expected struct timeval *, but argument is of type struct timeval *"
a fun error message? C considers a 'struct foo' mentioned inside a
function argument to be a distinct type from 'struct foo' declared on
the global level, but only if the in-function definition comes first. So
we need to ensure that struct timeval is declared (either fully, or
forward-declared) before we declare select() and pselect(). This was
taken care of by including <sys/time.h>, but
https://github.com/SerenityOS/serenity/pull/20044 made it so that
<sys/time.h> itself includes <sys/select.h>. So if the user's program
includes <sys/time.h> (before possibly including <sys/select.h>), then
<sys/select.h>'s include of <sys/time.h> will turn into a no-op (since
<sys/time.h> is already being included), yet there will not have been a
struct timeval definition yet, and we'd get the fun error message.
Fix this by including <Kernel/API/POSIX/sys/time.h> instead of
<sys/time.h>