Problem:
Cross-compilation issues encountered when building Neovim for WASM.
When cross-compiling, three issues occur:
1. `-Wl,--no-undefined` — not supported by `wasm-ld`
2. `-lutil` — not available in the Emscripten sysroot
3. Doc generation fails because CMake tries to execute `$<TARGET_FILE:nvim_bin>` on the host machine, which fails because the binary is not native to the host. It fails with `/bin/sh: nvim.js: Permission denied`
Solution:
The fix includes skipping `-Wl,--no-undefined` and `-lutil` with `NOT CMAKE_CROSSCOMPILING` and adding `NVIM_HOST_PRG` variable to `runtime/CMakeLists.txt` so when cross-compiling, it uses a host native nvim binary for doc generation instead of using the cross-compiled target.
8aacce90b4
