main/memdump: new aport
Utility to dump memory contents to standard output.
Uses "/dev/mem" and "/dev/kmem" to dump memory contents. Thus only works when the kernel has:
- CONFIG_DEVMEM=y
- CONFIG_DEVKMEM=y
- CONFIG_STRICT_DEVMEM=n
This work is based on the Debian package, except for a patch to make it work with musl libc.