[Toybox] musl intentionally broke chrt

[Rob Landley]

On 09/02/2017 04:08 PM, Owen Shepherd wrote:
> Per POSIX, <sched.h> is in ths [PS] (Process Scheduling) option. You can
> identify whether [PS] is implemented at compile time, by the value of
> _POSIX_PRIORITY_SCHEDULING defined in <unistd.h>.

I've found feature test macros to be a minefield for _years_, back to about:

http://lists.landley.net/pipermail/toybox-landley.net/2012-March/005251.html

But if you're saying "this is a compile-time probe you can use to work
around musl's breakage, as long as you're willing to first confirm that
all the other libc's out there _do_ provide this macro..." I'll put it
on the todo list.

But really, leaving musl broken here seems like what they explicitly
_want_. Maybe in chrt.c I can do an:

#ifndef _POSIX_THINGY
#warning musl commit XXXX broke the system calls this depends on
#endif

And call that a solution.

Rob