I hate the thing too even though I made it, and rather just get rid of
it. But we can't do that yet. In the meantime, this brings us more
inline with autoconf and will make it slightly easier for me to write a
pkg-config wrapper, which we need.
This has been broken since 5d18129ce8,
which updated idris from 1.3.0 to 1.3.1, which included
https://github.com/idris-lang/Idris-dev/pull/4472 as the cause of the
error. I'm still not entirely sure why this broke it though.
This now way should be rather future proof, it uses NIX_CFLAGS to pass
gpm link flags to our CC wrapper directly. The
`NIX_CC_WRAPPER_${stdenv.cc.infixSalt}_TARGET_HOST` part I'm pretty sure
is needed for the CC wrapper to know that those CFLAGS are meant for the
cc running on the HOST.
Previously idris used the C compiler from PATH for the C backend, which
means that the results and whether it even succeeds can vary between
systems (e.g. if a Nix-built Idris was used on a super old Linux system,
the cc installed there might not even work for Idris' C).
To make this more predictable, this commit sets the IDRIS_CC env var,
which Idris will prefer over searching in PATH, to a Nix-provided gcc
executable, given that it is not already set, so it's still possible to
override.
Fixes #10450
When compiling packages with -o the executable invokes gcc.
There is no compile time flag to control this invocation so for
now we create a wrapper which provides the dependency at runtime.
