[ccache] gmake and ccache conspiring together in creating gremlins

[Sam Varshavchik]

On Sun, Feb 7, 2021 at 7:59 AM Joel Rosdahl <joel at rosdahl.net> wrote:

> From my perspective, I don't see anything wrong with ccache dup-ing stderr – I
> guess the bug can be triggered by the user running something like
>
>   exec 3>&2
>
> in the shell as well.
>
> I can think of an easy workaround for the problem: only dup2 stderr when running
> the preprocessor or compiler. Done in
> <https://github.com/ccache/ccache/commit/c4284c78e9ff286ee5208f449af4c2aaba062d37>.

In the interim I discovered a workaround that seems to work, for
anyone who's also affected by this. Instead of setting CCACHE_PREFIX
to distcc, I pointed CCACHE_PREFIX to this:

#! /bin/sh

unset MFLAGS ${!MAKE@}
exec distcc "$@"

This clears make variables from the environment and when the linker
invokes make for ...whatever it needs to invoke it for, against a
manufactured makefile it generates on the fly... it doesn't go look
for the job server file descriptors, and go sideways.