idrisPackages: Fix linking to gmp library and cc

[infinisil]

Fixes #54579 and probably #52796

Ping @ar1a @marsam @shmish111 @mpickering

This has been broken since 5d18129,
which updated idris from 1.3.0 to 1.3.1, which included
idris-lang/Idris-dev#4472 as the cause of the
error. I'm still not entirely sure why this broke it though.

This 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.

The second commit just switches to stdenv's cc.

Things done

• Tested using sandboxing (nix.useSandbox on NixOS, or option sandbox in nix.conf on non-NixOS)
• Built on platform(s)
  • NixOS
  • macOS
  • other Linux distributions
• Tested compilation of all pkgs that depend on this change using nix-shell -p nix-review --run "nix-review wip"
• Tested execution of all binary files (usually in ./result/bin/)
• Determined the impact on package closure size (by running nix path-info -S before and after)
• Assured whether relevant documentation is up to date
• Fits CONTRIBUTING.md.

---

[infinisil]

@GrahamcOfBorg build idrisPackages.contrib

[infinisil]

Okay well that's weird. I tried building idrisPackages.contrib locally on my mac, which failed with an error that some Idris typeclass wasn't known (DecEq specifically). I am running a very outdated macOS and nix version though, so not sure. @GrahamcOfBorg seems to not have had any problems. Let's try a couple more libraries

@GrahamcOfBorg build idrisPackages.effects idrisPackages.glfw idrisPackages.html idrisPackages.http idrisPackages.idrisscript idrisPackages.pipes idrisPackages.webgl idrisPackages.yaml

And also some of the currently failing ones on Darwin:

@GrahamcOfBorg build idrisPackages.bi idrisPackages.config idrisPackages.electron idrisPackages.eternal idrisPackages.ipkgparser idrisPackages.mhd

[infinisil]

State of builds:

• On x86_64, everything builds
• On aarch, there's lots of timeouts, but no failures
• For the usually succeeding effects, glfw, ... packages, on darwin the contrib dependency now failed, even though it succeeded when I told it to build it earlier.. It failed with the same error I encountered regarding DecEq, maybe an impurity? This is the check with idrisPackages.contrib failing as a dependency: https://github.com/NixOS/nixpkgs/pull/58319/checks?check_run_id=87664056, and this is the one where it succeeded standalone: https://github.com/NixOS/nixpkgs/pull/58319/checks?check_run_id=87621971. I doubt that the different master version at these different times would've had an influence. @grahamc Can you perhaps check what versions of macOS these two builds used?
• For the usually failing bi, config, ..., on darwin only two of them failed, soo success?

[infinisil]

@GrahamcOfBorg build idrisPackages.contrib

[infinisil]

@GrahamcOfBorg build idrisPackages.contrib

[ar1a]

This closes #54579

[infinisil]

@GrahamcOfBorg build idrisPackages.contrib

[infinisil]

Doesn't solve the darwin issue.. I have no idea what's up with that tbh. Maybe something during the compilation of Prelude failed, making DecEq unavailable, dunno

This is the error for future reference:

Type checking ./Control/Isomorphism/Extra.idr
./Control/Isomorphism/Extra.idr:14:9:
   |
14 | swapped : DecEq a => (l : a) -> (r : a) -> Iso a a
   |         ^
When checking type of Control.Isomorphism.Extra.swapped:
No such variable DecEq

builder for '/nix/store/qib47cxnxl50vak43a0vk07rzmcvj57f-idris-contrib-1.3.1.drv' failed with exit code 1

I think I'll just merge this for now, idris currently is in an almost unusable state, so anything is an improvement.

[infinisil]

Not sure what to do about this right now. There's clearly a regression here, on my mac idrisPackages.contrib doesn't build anymore, but no idea where it comes from.

[ar1a]

you may get some insight from #idris or perhaps create an issue

[infinisil]

I'll just merge this now, idris is almost unusable without this

[infinisil]

Seems to build just fine on macOS Mojave, but not on High Sierra. So this problem should automatically disappear as hydra and people update their version

[rycee]

Been playing around with Idris and notice that this issue seem to affect 19.03, would any mind if I backport this? Seems to work well for me.

[infinisil]

@rycee Sounds good

[rycee]

Cool, done 🙂