c-ares @1.16.1 does not build on PPC Tiger, Mac OS X 10.4.11, because "'for' loop initial declaration used outside C99 mode"

[ballapete (Peter "Pete" Dyballa)]

  CC       libcares_la-ares_getnameinfo.lo
  CC       libcares_la-ares_getsock.lo
  CC       libcares_la-ares_init.lo
ares_init.c: In function 'init_by_resolv_conf':
ares_init.c:1614: error: 'for' loop initial declaration used outside C99 mode
ares_init.c:1643: error: 'for' loop initial declaration used outside C99 mode
make[2]: *** [libcares_la-ares_init.lo] Error 1
make[2]: Leaving directory `/opt/local/var/macports/build/_opt_local_var_macports_sources_nue.de.rsync.macports.org_macports_release_tarballs_ports_net_c-ares/c-ares/work/c-ares-1.16.1'
make[1]: *** [all-recursive] Error 1

[ballapete (Peter "Pete" Dyballa)]

Main.log from PPC Tiger

[ballapete (Peter "Pete" Dyballa)]

configure reports:

configure: No compiler with C++11 support was found

so it might be recommended to use GCC 7 or such.

[ballapete (Peter "Pete" Dyballa)]

It worked to put the line

configure.cflags-append -std=c99

into Portfile. Applying this change on the command line failed. The above mentioned warning was reported again.

[tobypeterson]

The code in question hasn't changed, but it appears that there was a configuration change that now causes it to be built. From CHANGES: "MacOS: Enable libresolv support for retrieving DNS servers like iOS does."

[tobypeterson]

In 5766b81f3b4df47e18b5d6b46982cb6438d0662c/macports-ports (master):

c-ares: build with non-C99 compilers, fixes #60550

[tobypeterson]

I opted to patch out the C99-ism; seems less risky than changing the -std version for everyone.

[ryandesign (Ryan Carsten Schmidt)]

Replying to ballapete:

It worked to put the line

configure.cflags-append -std=c99

into Portfile. Applying this change on the command line failed. The above mentioned warning was reported again.

That's correct. MacPorts does not support for appending to, deleting from, or otherwise modifying portfile variables from the command line. It only supports overwriting them entirely, which can be used as a diagnostic tool.

Replying to tobypeterson:

I opted to patch out the C99-ism; seems less risky than changing the -std version for everyone.

That's fine but note that clang has always defaulted to c99 mode so the only thing that setting -std=c99 would change would be to fix the build failure with Apple's old gcc that defaulted to c89. If upstream adopts more c99isms such that patching them out becomes cumbersome, it wouldn't be terrible to force c99 mode, since older compilers do support that. We've done it in several other ports before.

[tobypeterson]

Sure, forcing C99 probably isn’t a big deal. However, I suspect the approach I’ve taken is what upstream would do anyway - the project as a whole has no other usage of C99 features.