In reply to @quadradical:federated.nexus
Alrighty, another cross compile error :)

error: builder for '/nix/store/wlf1hfax3y1qb1z246qc0hvznq9r5nbv-bind-aarch64-unknown-linux-gnu-9.20.11.drv' failed with exit code 1;
       last 25 log lines:
       > checking for library containing backtrace_symbols... none required
       > checking for backtrace_symbols... yes
       > checking for IPv6 structures... yes
       > checking for strlcpy... yes
       > checking for strlcat... yes
       > checking for strnstr... no
       > checking for libedit... no
       > checking for libeditline... no
       > checking for readline... no
       > checking for chroot... yes
       > checking for libcap... yes
       > checking for tzset... yes
       > checking for optarg declaration... yes
       > checking for st_mtim.tv_nsec... yes
       > checking for if_nametoindex... yes
       > checking for uchar.h... yes
       > checking compiler support for __builtin_unreachable()... yes
       > checking compiler support for __builtin_clz... yes
       > checking compiler support for __builtin_add_overflow()... yes
       > checking compiler support for __builtin_sub_overflow()... yes
       > checking compiler support for __builtin_mul_overflow()... yes
       > checking for libfstrm libprotobuf-c... yes
       > checking for fstrm_capture... no
       > checking for protoc-c... no
       > configure: error: protoc-c compiler not found
       For full logs, run 'nix log /nix/store/wlf1hfax3y1qb1z246qc0hvznq9r5nbv-bind-aarch64-unknown-linux-gnu-9.20.11.drv'.
error: 1 dependencies of derivation '/nix/store/qmw9hxybmr6wpn5l5fzac19154a87f3y-bind-aarch64-unknown-linux-gnu-9.20.11_fish-completions.drv' failed to build
error: 1 dependencies of derivation '/nix/store/khaqk99n0qvsgimcwv0xccm5idkdrrjc-man-paths.drv' failed to build
error: 1 dependencies of derivation '/nix/store/4xkzi9cgaymn3b6hv8zciz54hhkpr3gk-system-path.drv' failed to build
error (ignored): error: cannot unlink 'ruby-3.3.8' in directory '/nix/var/nix/builds/nix-build-ruby-aarch64-unknown-linux-gnu-3.3.8.drv-0': Directory not empty
error: 1 dependencies of derivation '/nix/store/j4pa68jw1j8hlz0arrslhwkrwn48rsk3-etc.drv' failed to build
error: 1 dependencies of derivation '/nix/store/zffzw9njkqvnjzcln3zmq28nvq5jqq6g-nixos-system-quadphone-25.11.20250803.5b09dc4.drv' failed to build
error (ignored): error: cannot unlink 'man' in directory '/nix/var/nix/builds/nix-build-systemd-minimal-aarch64-unknown-linux-gnu-257.6.drv-0/source': Directory not empty
error: 1 dependencies of derivation '/nix/store/j4mmybnicx5jrdz9glzq1nac0pm05s21-image.drv' failed to build

Any ideas? Thanks :D

error: builder for '/nix/store/10w675y81lc7bnljwk5xzdp0dqibj0ym-ruby-aarch64-unknown-linux-gnu-3.3.8.drv' failed with exit code 2;
       last 25 log lines:
       >     |
       > 750 |         if let Some(cfunc_name_to_idx) = CFUNC_NAME_TO_IDX.as_mut() {
       >     |                                          ^^^^^^^^^^^^^^^^^^^^^^^^^^ mutable reference to mutable static
       >     |
       >     = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/static-mut-references.html>
       >     = note: mutable references to mutable statics are dangerous; it's undefined behavior if any other pointer to the static is used or if any other reference is created for the static while the mutable reference lives
       >
       > warning: creating a mutable reference to mutable static
       >    --> ./yjit/src/stats.rs:751:31
       >     |
       > 751 |             let call_counts = CFUNC_CALL_COUNT.as_mut().unwrap();
       >     |                               ^^^^^^^^^^^^^^^^^^^^^^^^^ mutable reference to mutable static
       >     |
       >     = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/static-mut-references.html>
       >     = note: mutable references to mutable statics are dangerous; it's undefined behavior if any other pointer to the static is used or if any other reference is created for the static while the mutable reference lives
       >
       > warning: 17 warnings emitted
       >
       > touch yjit/target/release/libyjit.a
       > partial linking yjit/target/release/libyjit.a into yjit/target/release/libyjit.o
       > /nix/store/g3hp4ilgnq77kycj57an658s28k2h1pp-aarch64-unknown-linux-gnu-binutils-2.44/bin/aarch64-unknown-linux-gnu-ld: yjit/target/release/libyjit.a(yjit.10tuhdtq5iclk7uhuxsxfkyg1.rcgu.o): Relocations in generic ELF (EM: 62)
       > /nix/store/g3hp4ilgnq77kycj57an658s28k2h1pp-aarch64-unknown-linux-gnu-binutils-2.44/bin/aarch64-unknown-linux-gnu-ld: yjit/target/release/libyjit.a(yjit.10tuhdtq5iclk7uhuxsxfkyg1.rcgu.o): Relocations in generic ELF (EM: 62)
       > /nix/store/g3hp4ilgnq77kycj57an658s28k2h1pp-aarch64-unknown-linux-gnu-binutils-2.44/bin/aarch64-unknown-linux-gnu-ld: yjit/target/release/libyjit.a(yjit.10tuhdtq5iclk7uhuxsxfkyg1.rcgu.o): error adding symbols: file in wrong format
       > make: *** [yjit/yjit.mk:48: yjit/target/release/libyjit.o] Error 1
       > make: *** Waiting for unfinished jobs....
       For full logs, run 'nix log /nix/store/10w675y81lc7bnljwk5xzdp0dqibj0ym-ruby-aarch64-unknown-linux-gnu-3.3.8.drv'.
error: 1 dependencies of derivation '/nix/store/ay6j2j4zg12sbs8jz8bw9r057bcb4sxc-unity-test-aarch64-unknown-linux-gnu-2.6.1.drv' failed to build
error: 1 dependencies of derivation '/nix/store/ps5x4gn7zpfp4k9aq3lm1i36djdisqqz-remove-fetchcontent-usage.patch.drv' failed to build
error: 1 dependencies of derivation '/nix/store/p602213sl9z2ikp6wljv3h0brvbac1kv-iniparser-aarch64-unknown-linux-gnu-4.2.6.drv' failed to build
error: 1 dependencies of derivation '/nix/store/fy0s91xlvk5d8p01mxindk1rcwfm1vcn-libndctl-aarch64-unknown-linux-gnu-82.drv' failed to build
error: 1 dependencies of derivation '/nix/store/frqmb2a4x46rmwdzzj5lvcnmnsnixbsn-libblockdev-aarch64-unknown-linux-gnu-3.3.0.drv' failed to build
error: 1 dependencies of derivation '/nix/store/rsz76hnrhx591arjv3znhjmd0b4j92yr-etc.drv' failed to build
error (ignored): error: cannot unlink 'nix-build-spidermonkey-aarch64-unknown-linux-gnu-128.5.0.drv-0' in directory '/nix/var/nix/builds': Directory not empty
error: 1 dependencies of derivation '/nix/store/k8zkxmzqhfksa41ilhawgygzq8b1d1vn-udisks-aarch64-unknown-linux-gnu-2.10.1.drv' failed to build
error: 1 dependencies of derivation '/nix/store/1bxab7jcg8pr1zdgxb3b3cqzmly80ay6-nixos-system-quadphone-25.11.20250806.c2ae88e.drv' failed to build
error: 1 dependencies of derivation '/nix/store/yd1cmgqg7626zzv4yiv00xc6wmky9897-ukify.conf.drv' failed to build
error: 1 dependencies of derivation '/nix/store/058cmhlhhg4slpbp2dk1f0lzqw6k2i82-image.drv' failed to build

In reply to @aidalgol:matrix.org
I maintain the package for an application that can launch Windows games under Proton, and upstream bundles a couple of native Windows executables for compatibility reasons. I have attempted to package these, but I am not sure whether my approach is acceptable in nixpkgs. Could I please get some feedback on this PR? The cross-built packages are heroic-epic-integration and galaxy-dummy-service.

error: builder for '/nix/store/psqdy3bj35mbqmmkbcsgv117pqglk1in-qtsvg-5.15.17.drv' failed with exit code 1;
       last 3 log lines:
       > Error: detected mismatched Qt dependencies:
       >     /nix/store/y9zd90mb7hn1g4zhsrfgl1kfqa8hjwf4-qtbase-5.15.17-dev
       >     /nix/store/r510hzq4jqdcikmar5c4iplyxdzhr5vn-qtbase-5.15.17-dev
       For full logs, run 'nix log /nix/store/psqdy3bj35mbqmmkbcsgv117pqglk1in-qtsvg-5.15.17.drv'.
error: 1 dependencies of derivation '/nix/store/rriq25m5rsp5xszas9hp9wi07iisv04l-qtdeclarative-5.15.17.drv' failed to build
error: 1 dependencies of derivation '/nix/store/46f9mkbq55g1na12x65a21vv0m4pdnd8-qtquickcontrols-5.15.17.drv' failed to build
error: 1 dependencies of derivation '/nix/store/6q027f3k159jli65a9q9pbd1gqgn7i1d-qtwayland-5.15.17.drv' failed to build
error: 1 dependencies of derivation '/nix/store/crja800vn0iglix53lr45cw0c7xk9mdp-wrap-qt5-apps-hook.drv' failed to build
error: 1 dependencies of derivation '/nix/store/x7qg17fg1fvsa66xjsbsraglv1c70i1r-zbar-aarch64-unknown-linux-gnu-0.23.93.drv' failed to build
error: 1 dependencies of derivation '/nix/store/358f77fxvb517vnmw6bwwjxs3qx2s62b-authenticator-aarch64-unknown-linux-gnu-4.6.2.drv' failed to build