Note that libc is what distinguish "native" software from "non-native"
in Jehanne: further C libraries can be ported to Jehanne, but this libc
will remain the main building block of the system.
Also note that a few files have not been ported from Harvey:
- 9sys/pushtls.c
- port/rijndael.c
- port/rijndael.tbl
- port/sha2.c
Pushtls.c depends on libmp and libsec so libc is not the appropriate place
for it. The other three will be moved to libsec.
