Merge remote-tracking branch 'rkeene/bug/aarch64-instr-and-syscall-wrong'

aarch64: syscall: unlink -> unlinkat

aarch64: syscall: mknod -> mknodat

Remove untested from RISC-V

Add missing instruction definition

This change adds a missing macro definition for the instructio
to set x1 to AT_FDCWD, which is needed for the symlink wrapper
around the syscall symlinkat()

Remove "const" from arguments for symlink() syscall wrappers

Merge remote-tracking branch 'fossy/variable-getting-bug'

Add failure stub for symlink on linux/knight

Add symlink for Linux/aarch64

Untested symlink support on RISC-V

Preliminary symlink system call wrapper support

Make variable getting to-spec

It is expected by the UEFI specification that when a variable is
retrieved with NULL data, the data length is 0. Previous behaviour in
M2libc did not conform.

It appears some UEFI implementations depend on this and some do not
(notably, EDK2 does not, but many bare metal platforms do).

Add assembly definitions for amd64 paging.

Merge remote-tracking branch 'fossy/fgets-eof'

Fix fgets behaviour when EOF reached

Typically fgets returns NULL when EOF occus and no characters have been
read. Align this behaviour with POSIX impls.

Fix armv7l bug and added support for 1_000_000 number strings

Add support for truncating open files.

uefi: chdir: return -1 if path does not exist.

cp from mescc-tools-extra relies on this.

ensure needed libraries are read first

A very rough prototype for strstr