xsel 1.2.0 fails to build on macOS 12.0.1

[derekschrock (Derek Schrock)]

$ sudo port install xsel
...
Error: Failed to build xsel: command execution failed
Error: See /opt/local/var/macports/logs/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_x11_xsel/xsel/main.log for details.
Error: Follow https://guide.macports.org/#project.tickets if you believe there is a bug.
Error: Processing of port xsel failed

...
:info:build if /usr/bin/clang -DHAVE_CONFIG_H -I. -I. -I.   -I/opt/local/include -isysroot/Library/Developer/CommandLineTools/SDKs/MacOSX12.sdk  -pipe -Os -isysroot/Libr
ary/Developer/CommandLineTools/SDKs/MacOSX12.sdk -arch x86_64 -fno-strict-aliasing -Wall -Werror -g -std=gnu99 -Wdeclaration-after-statement -Wno-unused -MT xsel.o -MD -
MP -MF ".deps/xsel.Tpo" -c -o xsel.o xsel.c; \
:info:build     then mv -f ".deps/xsel.Tpo" ".deps/xsel.Po"; else rm -f ".deps/xsel.Tpo"; exit 1; fi
:info:build xsel.c:372:14: error: 'fork' is deprecated: Use posix_spawn or fork [-Werror,-Wdeprecated-declarations]
:info:build   if ((pid = fork()) == -1) {
:info:build              ^
:info:build /Library/Developer/CommandLineTools/SDKs/MacOSX12.sdk/usr/include/unistd.h:604:1: note: 'fork' has been explicitly marked deprecated here
:info:build __deprecated_msg("Use posix_spawn or fork")
:info:build ^
:info:build /Library/Developer/CommandLineTools/SDKs/MacOSX12.sdk/usr/include/sys/cdefs.h:208:48: note: expanded from macro '__deprecated_msg'
:info:build         #define __deprecated_msg(_msg) __attribute__((__deprecated__(_msg)))
:info:build                                                       ^
:info:build xsel.c:382:14: error: 'fork' is deprecated: Use posix_spawn or fork [-Werror,-Wdeprecated-declarations]
:info:build   if ((pid = fork()) == -1) {
:info:build              ^
:info:build /Library/Developer/CommandLineTools/SDKs/MacOSX12.sdk/usr/include/unistd.h:604:1: note: 'fork' has been explicitly marked deprecated here
:info:build __deprecated_msg("Use posix_spawn or fork")
:info:build ^
:info:build /Library/Developer/CommandLineTools/SDKs/MacOSX12.sdk/usr/include/sys/cdefs.h:208:48: note: expanded from macro '__deprecated_msg'
:info:build         #define __deprecated_msg(_msg) __attribute__((__deprecated__(_msg)))
:info:build                                                       ^
:info:build 2 errors generated.
:info:build make[1]: *** [xsel.o] Error 1
:info:build make[1]: Leaving directory `/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_x11_xsel/xsel/wo
rk/xsel-1.2.0'
:info:build make: *** [all] Error 2
:info:build make: Leaving directory `/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_x11_xsel/xsel/work/
xsel-1.2.0'

[ryandesign (Ryan Carsten Schmidt)]

I have reported the bug to the developers of xsel for you ​here.

[ryandesign (Ryan Carsten Schmidt)]

However the last release of xsel was in 2008 so it may be dead. If anyone knows the fix for this issue, please contribute it to upstream, then notify us here.

[derekschrock (Derek Schrock)]

If you're open to getting it to just build, patching out the "#define vfork fork" in config.h post-configure should fix it. There's a number of other options for upstream however I don't it being fixed in a timely manner.

Is it possible for the port to patch around it until then?

[ryandesign (Ryan Carsten Schmidt)]

It is technically possible, of course. Though I can't say that I understand the issues at hand here.

[derekschrock (Derek Schrock)]

xsel's ​configure.ac has ​AC_FUNC_FORK which creates the macro:

#define vfork fork

This is added to "config.h" included in ​xsel.c before ​system headers.

macOS 12's ​<unistd.h> has the following:

...

#if !defined(_POSIX_C_SOURCE)
__deprecated_msg("Use posix_spawn or fork")
#endif
pid_t	 vfork(void) __WATCHOS_PROHIBITED __TVOS_PROHIBITED;
/* End XSI */
...

Since "config.h" with the above macro #define vfork fork that pid_t vfork ... turns in to pid_t fork ... So now any usage of fork() results in a depercation message.

The exact fix is still in question as mentioned ​here. Any one of those can be used. However, the easy ones would be to remove ​AC_FUNC_FORK from configure.ac or remove or #undef vfork the vfork macro after autoconf runs.

Assuming everything I said is true/correct. Removing AC_FUNC_FORK from configure.ac might be the easiest/safest? From my understanding AC_FUNC_FORK is only here for broken vfork/fork which isn't an issue on supported macOS version? `

[derekschrock (Derek Schrock)]

This works...?

​https://github.com/derekschrock/macports-ports/commit/ccdc6bc419feaaa00b378d28f3024ba88a3e1f79

[ryandesign (Ryan Carsten Schmidt)]

Great but

1. since this only fixes a build failure and does not change the functionality of existing successful builds on earlier OS versions the revision should not be increased;
2. you must check os.platform before you check os.arch; and
3. this should be a patchfile not a reinplace for the usual reasons.

You mentioned in the upstream bug that it may be an autoconf bug. If you think so, please file a bug report with them. I have not attempted to understand the issue in as much detail as you have and don't currently intend to do so; I'm busy with other things.

[derekschrock (Derek Schrock)]

Update the patch to x11/xsel instead of patching/replace but to default AC_FUNC_FORK's vfork function check to yes so in turn doesn't create the macro.

Reverted the revision bump and checked for darwin before os.major.

​https://github.com/derekschrock/macports-ports/commit/066d3a2b2c529d16856a5775221da52ca51fc1d5

[derekschrock (Derek Schrock)]

Any issues with the above commit? If not I can submit a pull request.

[ryandesign (Ryan Carsten Schmidt)]

Use eq instead of == when performing string comparisons in Tcl. And it's a good idea to add a comment in the Portfile, above your change, with a link to the upstream bug report that explains why it's there.

As for whether this fix is correct, as I've said, I have no information and take no responsibility for it. If this breaks something, I hope that you will follow up with any necessary fixes; I don't want to be involved.

[derekschrock (Derek Schrock)]

In a5e2d3e12ea03b0a6712a7f8efeab9049b428cc8/macports-ports (master):

xsel: disable check for autoconf vfork AC_FUNC_FORK

• disable check for autoconf AC_FUNC_FORK vfork checking caching to yes.
• AC_FUNC_FORK will create a #define vfork fork macro in config.h
• vfork has been mark depercated in macOS 12.
• This macro will mark fork() usage as depercated due to config.h being included before system header <unistd.h>.

Re: ​https://github.com/kfish/xsel/issues/42
Closes: #63748