[libmicrohttpd] macOS, gnu gcc, -no-cpp-precomp

[Chris Guiney]

I've been being vexed by the configure script using -no-cpp-precomp as a CFLAG if the host is found to be macOS

https://git.gnunet.org/libmicrohttpd.git/tree/configure.ac#n765

This flag has been removed from gcc, and according to the maintainers, hasn't been needed for many years

https://gcc.gnu.org/legacy-ml/gcc/2005-12/msg00368.html

I'm hoping that I can either persuade a maintainer to remove it, or provide instruction on how I might remove it -- I've never had to contribute to a GNU project, or contribute to a autoconf/automake build.

I find that if I do remove it, and run autoreconf, it's able to configure and compile cleanly.

It manifests as an error indicating that it can't find a suitable threading library:

CC=/opt/homebrew/bin/gcc-11 ./configure --prefix=/usr/local

... many lines of configure output ...

checking for pthread-config... no

checking for threading lib to use with libmicrohttpd (auto)... configure: error: No threading lib is available. Consider installing pthreads

but after viewing the config.log, one can find:

configure:21066: checking for target host OS

configure:21075: result: Darwin

configure:22010: checking whether /opt/homebrew/bin/gcc-11 is Clang

configure:22037: result: no

configure:22102: checking whether pthreads work with "-pthread" and "-lpthread"

configure:22213: /opt/homebrew/bin/gcc-11 -o conftest -no-cpp-precomp -fno-common -g -O2 -pthread   conftest.c -lpthread  >&5

gcc-11: error: unrecognized command-line option '-no-cpp-precomp'

For posterity, the output of gcc --version:

/opt/homebrew/bin/gcc-11 --version        

gcc-11 (Homebrew GCC 11.3.0_2) 11.3.0

Copyright (C) 2021 Free Software Foundation, Inc.

This is free software; see the source for copying conditions.  There is NO

warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

I should also note that it does build with clang -- I'm intentionally trying to use gcc

Any help is appreciated,

Chris