warning: implicit declaration of function ‘pselect’

[andersk@mit.edu]

If PERL_CFLAGS does not contain -D_GNU_SOURCE, then BarnOwl compiles with this warning:

select.c: In function ‘owl_select’:
select.c:416:3: warning: implicit declaration of function ‘pselect’

because pselect requires _POSIX_C_SOURCE >= 200112L || _XOPEN_SOURCE >= 600, either of which would require C99 mode on Solaris.

This was discovered on Gentoo, but can be tested on Ubuntu with a stupid change to configure.ac:

-PERL_CFLAGS=`perl -MExtUtils::Embed -e ccopts`
+PERL_CFLAGS=`perl -MExtUtils::Embed -e ccopts | sed 's/-D_GNU_SOURCE/-D_LARGEFILE64_SOURCE/'`

[andersk@mit.edu]

So, yeah. We could turn on C99 mode (via ​AC_PROG_CC_STDC or AC_PROG_CC_C99), or turn on _GNU_SOURCE (via ​AC_USE_SYSTEM_EXTENSIONS), and resign ourselves to allowing the code to start requiring one or the other. Or maybe we could conditionally enable _XOPEN_SOURCE=600 somehow, which sounds like an even worse idea.

[jgross@mit.edu]

Fixed by the g_main_loop branch (specifically commit 2c79eae5e102073224cebae432e5c3ca7122da9f). If we don't pselect anymore, we can't be warned about its implicit declaration.