Cross compilation

[davidgraeff]

Would you mind adding another patch for the Makefile?
The original quickjs Makefile already allows to set a CROSS_PREFIX. But they do it in a way that it would need to be explicitly set on the command line via make -e CROSS_PREFIX=...

If you add the following line, "CROSS_PREFIX" can be set by the cargo environment:

let content = Regex::new("CROSS_PREFIX=")?.replace_all(&content, "CROSS_PREFIX?=");

rust-quickjs/qjs-sys/build.rs

Line 39 in 645db1c

This allows to compile for aarch64 as a static musl binary for example, which is currently not possible:
PATH=$PATH:/path/to/musl/gcc/aarch64/bin CROSS_PREFIX=aarch64-linux-musl- cargo build --target aarch64-unknown-linux-musl