Feature/gcc ng

[angerman]

Motivation for this change

Things done

• Tested using sandboxing (nix.useSandbox on NixOS, or option build-use-sandbox in nix.conf on non-NixOS)
• Built on platform(s)
  • NixOS
  • macOS
  • other Linux distributions
• Tested via one or more NixOS test(s) if existing and applicable for the change (look inside nixos/tests)
• Tested compilation of all pkgs that depend on this change using nix-shell -p nox --run "nox-review wip"
• Tested execution of all binary files (usually in ./result/bin/)
• Fits CONTRIBUTING.md.

---

[angerman]

@Ericson2314 as I mentioned earlier...

This is a rather rough cut, and it doesn't allow me to build packages with it yet, due to some missing headers (e.g. mingw-w64) isn't properly injected into the CFLAGS, and as such building packages like zlib will fail with <stdio.h> not found.

The general idea:

1. configure gcc and build gcc (all-gcc) out of tree.
2. collect the build results and the source, and call this -prebuilt.
3. Use -prebuilt to actually install gcc (install-gcc) -- This is a gcc, with no libgcc, and no libc.
4. Build the libc (in my case that's msvcrt) -- now we have a gcc, with no libgcc, but a libc.
5. Build any additionally needed libraries (e.g. winpthreads)
6. Use -prebuilt to build libgcc (all-target-libgcc and install-target-libgcc). We could also build any other gcc component here, based off of the prebuilt tree.

Finally use 1+4+5+6 to actually have a proper cross gcc.

Any suggestions are welcome!

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PS: Yes, I tried to make this work in the existing gcc expression. I tried to follow the GNU/Hurd appraoch with the libpthreadCross, but could not make it work without constantly running into include/library issues.

[Ekleog]

Just a few comments, I don't know enough about both mingw and cross-compilation to say whether this is wanted or a good implementation :)

cc @Ericson2314 for a more general “is this a good idea?” review

[Ekleog]

Suggested change

	# bould out of tree. We don't use `pwd` in the `configureScript` so
	# build out of tree. We don't use `pwd` in the `configureScript` so

[Ekleog]

With the change below,

Suggested change

	{ fetchurl, stdenv, mingw_header, hostPlatform, buildPlatform }:
	{ fetchurl, stdenv, mingw_header }:

[Ekleog]

Isn't this setting all gcc to be msvcrt-based, thus breaking the package for non-windows?

[Ekleog]

Same here, won't setting the compiler to msvcrt break the package on non-windows?

[Ekleog]

Suggested change

	gmp mpfr libmpc #libelf
	gmp mpfr libmpc

Or add a comment as to why it is left here

[mmahut]

Are there any updates on this pull request, please?

[stale]

Thank you for your contributions.
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[Mindavi]

Pretty sure this is made obsolete by #132343. Please reopen if not.