On musl-based systems (Alpine), ldd returns exit code 0 for static
binaries, unlike glibc which returns 1. This causes install_busybox()
to reject all busybox binaries as "dynamically linked" on Alpine.
Fix by also accepting binaries whose executable name contains "static"
(i.e. busybox-static, busybox.static), which are the first two
candidates checked by the function. The generic "busybox" fallback
still relies on the ldd return code check.