Use nixpkgs crystal as base

[will]

This gets rid of all the custom building of Crystal and just leaves the wrapping the complier into a more friendly distribution with all of the common libraries included and some of the helper functions and such.

Nixpkgs has gotten better at updating to new crystal releases faster lately, and also they maintain all 4 main platforms so there isn't a need to do our own bootstrapping of aarch64-linux anymore.

The only real loss is that nixpkgs crystal doesn't build with the beta interpreter enabled. However that seems like a good tradeoff for being able to just always fetch the base complier from the main nix caches.

[will]

Static compilation works for aarch64-darwin, but there is something wrong with aarch64-linux at least. I'm not sure if it's worth spending time tracking that down at the moment.

[will]

I disabled checks for static builds, unless you have a quick idea of what is missing maybe @rbishop? I dont know why libevent would be unable to find symbols only when doing this static build and not the dynamic linking, since it's the same exact set of libraries.

[will@nixos:~]$ result/bin/crystal build a.cr
/nix/store/y00xcd5jqq6zlsqs24k8kxw94ppzmmwz-binutils-2.41/bin/ld: /nix/store/zpy6jb4zny70wfani7c2pfr0r5q1n3b3-libevent-static-aarch64-unknown-linux-musl-2.1.12/lib/libevent.a(evutil.o): in function `evutil_getenv_':
(.text+0x2cd0): undefined reference to `issetugid'

clang-15: error: linker command failed with exit code 1 (use -v to see invocation)

Error: execution of command failed with exit status 1: cc "${@}" -o /home/will/a
-rdynamic
-L/nix/store/fbd92bg0vgzlsvmzxhsgwqvgp0kl4k4i-boehm-gc-static-aarch64-unknown-linux-musl-8.2.4/lib
-L/nix/store/hmvsdnfi9s81bifahql3n6nxs7c0b7n7-gmp-with-cxx-static-aarch64-unknown-linux-musl-6.3.0/lib
-L/nix/store/zpy6jb4zny70wfani7c2pfr0r5q1n3b3-libevent-static-aarch64-unknown-linux-musl-2.1.12/lib
-L/nix/store/sff06r27nd3rjbs4v5g2476pnd0q17rc-libffi-static-aarch64-unknown-linux-musl-3.4.6/lib
-L/nix/store/iqn3id8fq7r1mfh72c9xdffvgwgps0sx-libxml2-static-aarch64-unknown-linux-musl-2.12.5/lib
-L/nix/store/vzqgd5r0znnmanqvsj9z6hlsyid70ny8-libyaml-static-aarch64-unknown-linux-musl-0.2.5/lib
-L/nix/store/qwzyn8qwvnf4g1nz13zm8926k1qai1c0-openssl-static-aarch64-unknown-linux-musl-3.0.13/lib
-L/nix/store/2v9x25iywsfsv7vh8j7hhbjkfw0d305b-pcre2-static-aarch64-unknown-linux-musl-10.43/lib 
-L/nix/store/hmcj23v98qxl9akviziqhcqhcvs0n8wf-zlib-static-aarch64-unknown-linux-musl-1.3.1/lib 
-L/nix/store/nqw7zkzp9mmi0avixxn0szlxxhvh3igx-boehm-gc-8.2.4/lib
 -L/nix/store/axgxx85mf3r5bcrg1w5i6fw143jx983y-pcre2-10.43/lib 
-L/nix/store/pdwx7snh84yxpxk1n2q4zzsczl5zwg9h-libevent-2.1.12/lib 
-L/nix/store/5wihi8hmnrirk6f7vg40p6kqivgi4z9j-libyaml-0.2.5/lib 
-L/nix/store/1ch4q190znxnxdbqy278f73fs7834b5g-zlib-1.3.1/lib 
-L/nix/store/8bj9m4jhq1193db8xxmfax5jnsg1i5f8-libxml2-2.12.5/lib 
-L/nix/store/n3m4sqchz4a45az2yb3xw1i1lrlzxh84-openssl-3.0.13/lib 
-lpcre2-8 -L/nix/store/nqw7zkzp9mmi0avixxn0szlxxhvh3igx-boehm-gc-8.2.4/lib 
-lgc -lpthread -ldl -lpthread 
-L/nix/store/pdwx7snh84yxpxk1n2q4zzsczl5zwg9h-libevent-2.1.12/lib 
-levent -lrt -lpthread -ldl

`