[oe] [meta-oe][PATCH] xterm: Fix latent issue found with musl

[Adrian Bunk]

On Thu, Dec 12, 2019 at 12:22:52PM -0800, Khem Raj wrote:
>...
> +Upstream-Status: Pending

Not upstreamed OE-only musl patches create a technical debt.

>...
> +there is no test to define HAVE_GRANTPT_PTY_ISATTY

Is the definition in xterm_io.h not working?

>...
> +_POSIX_SOURCE is app-defined not system

This is true for musl, not for glibc.

The handling of _POSIX_SOURCE and _POSIX_VERSION differs between musl 
and glibc due to glibc supporting older POSIX versions, and glibc also 
supporting developers of portable code to select some specific older 
POSIX version.

>...
> +-#if defined(_POSIX_SOURCE) || defined(SVR4) || defined(__convex__) || defined(__SCO__) || defined(__QNX__)
> ++#if defined(_POSIX_VERSION) || defined(SVR4) || defined(__convex__) || defined(__SCO__) || defined(__QNX__)
> + 	    int pgrp = setsid();	/* variable may not be used... */
> + #else
> +         int pgrp = getpid();
>...

So this was caused by musl not supporting older versions of POSIX,
where _POSIX_SOURCE was part of the standard.

The proper fix would be an autoconf test for setsid().

cu
Adrian