Makefile: Fix for {Net,Free,Open}BSD and generic $CFLAGS in environ

[lanodan]

• CFLAGS ?= inherits from the environment, so shouldn't have -std=c99
• In practice everything but Darwin uses -shared
• NetBSD has a broken CMSG_DATA macro when -D_POSIX_C_SOURCE=200809L is set
  their bug but probably better to make it work for now

[feld]

This has been compile tested on:

FreeBSD 14
OpenBSD 7.4
NetBSD 9.3
MacOS 14 Sonoma
Debian 12.2 Bookworm

[feld]

There may be a bug with Alpine Linux? Investigating...

==> exile
mkdir -p priv
cc -std=c99 -I/usr/local/lib/erlang/usr/include -shared -D_POSIX_C_SOURCE=200809L -Wall -Werror -Wextra -Wno-unused-parameter -pedantic -O2 -fPIC c_src/exile.c -o priv/exile.so
mkdir -p priv
cc -std=c99 -Wall -Werror -Wextra -Wno-unused-parameter -pedantic -O2 -fPIC c_src/spawner.c -o priv/spawner
c_src/spawner.c: In function ‘exec_process’:
c_src/spawner.c:115:25: error: ‘O_CLOEXEC’ undeclared (first use in this function); did you mean ‘FD_CLOEXEC’?
  115 |   if (set_flag(r_cmdin, O_CLOEXEC) < 0 || set_flag(w_cmdout, O_CLOEXEC) < 0 ||
      |                         ^~~~~~~~~
      |                         FD_CLOEXEC
c_src/spawner.c:115:25: note: each undeclared identifier is reported only once for each function it appears in
make: *** [Makefile:24: priv/spawner] Error 1
could not compile dependency :exile, "mix compile" failed. You can recompile this dependency with "mix deps.compile exile", update it with "mix deps.update exile" or clean it with "mix deps.clean exile"

[lanodan]

[2024-01-22 10:35:25-0800] @feld

There may be a bug with Alpine Linux? Investigating...

Addressed with adding the POSIX define on everything but NetBSD, works on NetBSD 9.3 and *-linux-{gnu,musl}.

[feld]

The force pushed version appears to have fixed it

[feld]

MacOS is breaking with the latest change as it doesn't like -D_POSIX_C_SOURCE=200809L which was previously not getting set for MacOS

[feld]

MacOS is breaking with the latest change as it doesn't like -D_POSIX_C_SOURCE=200809L which was previously not getting set for MacOS

MacOS build now working

[akash-akya]

Thanks for adding the support and general Makefile cleanup!

[feld]

bleh, I just did a clean build on my FreeBSD box and it's also blowing up with -D_POSIX_C_SOURCE=200809L. I guess I missed testing the final variant of this Makefile where that value was coming through to FreeBSD.

[akash-akya]

@feld so the Makefile still does not work for FreeBSD is it? If you have a fix, please share