New comment by sgn on void-packages repository

https://github.com/void-linux/void-packages/pull/28919#issuecomment-782619454

Comment:
Adding:
```sh
lt_cv_sys_lib_dlsearch_path_spec="/usr/lib64 /usr/lib32 /usr/lib /lib /usr/local/lib"
```
into common-linux wouldn't work, because that file will be sourced in cross-compilation only.

Even if we source it in native, it wouldn't work because `./configure` may be run in `do_build` (`libtool` package does that).

I think there are 2 possible solutions:
- export from `common/xbps-src/libexec/build.sh`
- Put `/usr/lib32` into `/etc/ld.so.conf.d/*` unconditionally, add `/usr/lib64` for 64 bit system, add `/etc/ld.so.conf` into `base-files` for `musl` (to avoid rebuilding cross compiler).