[libc-eglibc] Rewrite part of the code

Rewrite part of the code to better match the rest.
Most notably, rewrite handling of:
if [ ... ] && [ ... ]
to:
if [ ... -a ... ]

This has the positive side effect of calling "[" only once, although
"[" is probably a shell built-in.

#!/bin/sh

SKIP_ME="### CT_NG SKIP ME ###"

skip_me=$(($(cat "${0}" |@@grep@@ --binary-files=text -o -b -E "^${SKIP_ME}$" |cut -d : -f 1)+${#SKIP_ME}+1))

dd if="${0}" bs=${skip_me} skip=1 2>/dev/null |bzcat

exit 0

### CT_NG SKIP ME ###