[musl] [PATCH] add support for POSIX_SPAWN_SETSID

[Zack Weinberg]

On Sat, Apr 22, 2017 at 7:19 PM, Rich Felker <dalias@libc.org> wrote:
>> >  #define POSIX_SPAWN_SETSIGMASK 8
>> >  #define POSIX_SPAWN_SETSCHEDPARAM 16
>> >  #define POSIX_SPAWN_SETSCHEDULER 32
>> > +#define POSIX_SPAWN_SETSID 64
>>
>> This overlaps with the glibc value for POSIX_SPAWN_USEVFORK; while we
>> don't implement it, we also don't want to have mismatched constant
>> ABI.
...
> Thanks for all your work on this! Based on the glibc patch review, I'm
> changing the error condition from !=0 to <0, and of course changing
> the flag value to 128 to match.

May I suggest that musl include a note in its headers, explaining that
bit 64 is reserved to avoid an ABI conflict with glibc?  Then the next
time there's an addition, there will be less confusion.

zw