New comment by zlice on void-packages repository

https://github.com/void-linux/void-packages/pull/48480#issuecomment-1948405859

Comment:
i see `build-helper/rust.sh : 28` has `export BINDGEN_EXTRA_CLANG_ARGS+=" --sysroot=${XBPS_CROSS_BASE} -I${XBPS_CROSS_BASE}/usr/include"`

not sure how or where that's used? 1 or 2 other templates seem to have the var.

try this in mesa template? idk rust really but quick search points to the bindgen cross build var (may want to do for only musl??? dont think it would matter but)

```sh
  if [ "$CROSS_BUILD" ]; then
    BINDGEN_INCLUDE_FLAGS=$( $CPP -x c++ -v /dev/null -o /dev/null 2>&1 | \
      sed -n '/#include <...> search starts here:/,/End of search list./p' | \
      sed '1,1d;$d' | sed  's/^ /-I/' | paste -s )

    # fix compiler detection for botan:
    # https://github.com/randombit/botan/blob/63d51cb1ab08849d8ece329811b61f8c9abebbcf/configure.py#L2888
    export CXX="${XBPS_CROSS_TRIPLET}-g++"

    export BINDGEN_CFLAGS="--target=$XBPS_CROSS_TRIPLET \
      --sysroot=${XBPS_CROSS_BASE} ${BINDGEN_INCLUDE_FLAGS}"
```