mem_alloc_pages/mem_free_block/mem_get_page/mem_info, implemented twice:
mem_estex.c via ESTEX $3C-$3E (INFOMEM/GETMEM/FREEMEM), mem_bios.c via
the BIOS $C0/$C2-$C4/$C6 EMM_FN* calls. lib/Makefile already listed both
under LIBC_C.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
