fix diet libc build breaks for e4crypt and fallocate

Diet libc doesn't support syscall correctly, but it does have
add_key() and keyctl() in libc (although glibc does not).  So change
e4crypt to use add_key() and keyctl() directly if they are available.

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
5 files changed