lchmod: port back to AIX 7.2 Problem reported by Bruno Haible in: https://lists.gnu.org/r/bug-gnulib/2022-06/msg00075.html * lib/lchmod.c: Include string.h, for strlen. (lchmod): Do not depend on HAVE_READLINK since we now depend on the readlink module. Check for AIX 7.2 bug. * m4/lchmod.m4 (gl_PREREQ_LCHMOD): Do not check for readlink since we now depend on the readlink module. * modules/lchmod (Depends-on): Depend on readlink.