libc: Import files from FreeBSD

From commit aafd1cf4235d78ce85b76d7da63e9589039344b3:

- sys/sys/endian.h
- sys/arm/include/endian.h
- sys/arm64/include/endian.h
- sys/sys/errno.h
- lib/libc/strchr.c
- lib/libc/strcmp.c
- lib/libc/strncmp.c
- lib/libc/strnlen.c

strcasecmp() hasn't been imported.

Change-Id: I8a0787aec9ba8960a008fb5c66f7a73c84919b93
Signed-off-by: Antonio Nino Diaz <antonio.ninodiaz@arm.com>
8 files changed