Describe the bug
pretty-simple breaks with (full log):

[3 of 7] Compiling Text.Pretty.Simple.Internal.ExprParser ( src/Text/Pretty/Simple/Internal/ExprParser.hs, dist/build/Text/Pretty/Simple/Internal/ExprParser.o, dist/build/Text/Pretty/Simple/Internal/ExprParser.dyn_o )
attempting to use module ‘pretty-simple-4.0.0.0-7XPG9KFSjjE3sIrbReVEek:Text.Pretty.Simple.Internal.Expr’ (src/Text/Pretty/Simple/Internal/Expr.hs) which is not loaded
builder for '/nix/store/0w5bsr5gv2jcbr6f2nr9i90cyl2pxjkz-pretty-simple-4.0.0.0-aarch64-unknown-linux-musl.drv' failed with exit code 1
cannot build derivation '/nix/store/hv2038drs08xyzanb4h42v1zmsb8fbvp-hledger-lib-1.21-aarch64-unknown-linux-musl.drv': 1 dependencies couldn't be built
building '/nix/store/i8qfka6jlkgzyym1c2c88k47xwl65ch7-regex-tdfa-1.3.1.0-aarch64-unknown-linux-musl.drv'...
cannot build derivation '/nix/store/rnbkxxi53wy066z1wlfb3a5mb8090mmg-hledger-1.21-aarch64-unknown-linux-musl.drv': 1 dependencies couldn't be built
error: build of '/nix/store/rnbkxxi53wy066z1wlfb3a5mb8090mmg-hledger-1.21-aarch64-unknown-linux-musl.drv' failed

To Reproduce
Steps to reproduce the behavior

LC_ALL=C NIX_PATH=nixpkgs=https://github.com/NixOS/nixpkgs/archive/830ef6422f643d5c639fd79bca834c726787ec51.tar.gz nix-build -E 'import <nixpkgs> { compiler = (import <nixpkgs> {}).haskell.packages.ghc8104; system = "aarch64-linux";}' --arg crossSystem '(import <nixpkgs> {}).lib.systems.examples.aarch64-multiplatform-musl' -A pkgsStatic.haskellPackages.pretty-simple

Expected behavior
Static binary for aarch64 should be built.

Notify maintainers

@cdepillabout

Metadata
Please run nix-shell -p nix-info --run "nix-info -m" and paste the result.

 - system: `"x86_64-linux"`
 - host os: `Linux 5.11.13-arch1-1, Arch Linux, noversion`
 - multi-user?: `yes`
 - sandbox: `yes`
 - version: `nix-env (Nix) 2.3.8`
 - channels(root): `"nixpkgs-21.03pre250093.0da76dab4c2"`
 - nixpkgs: `/nix/var/nix/profiles/per-user/root/channels/nixpkgs`

Maintainer information:

# a list of nixpkgs attributes affected by the problem
attribute:
# a list of nixos modules affected by the problem
module: