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.
