Use chez-racket from mainline Nixpkgs

[L-as]

NixOS/nixpkgs#131833 has been merged.

[L-as]

For some reason I get this:

239/239: Building Idris.Main (src/Idris/Main.idr)
make -C libs/prelude IDRIS2=/build/jpwfg1aibmrcyv0a40p91y4hf7n16vx4-source/build/exec/idris2 IDRIS2_INC_CGS=chez IDRIS2_PATH="/build/jpwfg1aibmrcyv0a40p91y4hf7n16vx4-source/libs/prelude/build/ttc:/build/jpwfg1aibmrcyv0a40p91y4hf7n16vx4-source/libs/base/build/ttc:/build/jp>
make[2]: Entering directory '/build/jpwfg1aibmrcyv0a40p91y4hf7n16vx4-source/libs/prelude'
/build/jpwfg1aibmrcyv0a40p91y4hf7n16vx4-source/build/exec/idris2 --build prelude.ipkg
/build/jpwfg1aibmrcyv0a40p91y4hf7n16vx4-source/build/exec/idris2: line 15: /build/jpwfg1aibmrcyv0a40p91y4hf7n16vx4-source/build/exec/idris2_app/idris2.so: Permission denied

Will try to figure out why this happens.

EDIT: The problem seems to be that idris2.so is empty. Not sure what the cause of this is. Some error silently ignored earlier in the build?

[L-as]

FWIW it seems like something broke aarch64-linux, unrelated to the change in this PR. Doesn't make much sense to merge this though if it's broken, even if it's unrelated to this change.

[L-as]

@loovjo Does this work for you? I assume you use Idris on tarm64osx.

[L-as]

Given that the old commit can no longer be fetched, and since the problem with aarch64-linux/tarm64le seems separate, this should probably be merged.