* exec/configure.ac (MIPS_NABI): Always define to 1 on
mips64el-*-linux*.

* exec/config-mips.m4.in (DADDI2, DADDI3): Disable at-clobbering
by assembler macros expressly.

* exec/loader-mips64el.s: Adapt from loader-mipsel.s.

* exec/configure.ac (exec_cv_as_daddi): Properly escape reg
names.

* exec/exec.c (struct exec_jump_command, exec_0): Don't define
or set `fpu_mode' if __LP64__.

* exec/exec.h (struct exec_tracee): New field `callno'.

* exec/trace.c (process_system_call): Always record the current
system call number in TRACEE lest it should be required once it
has been overwritten upon the syscall's completion.
(seccomp_system_call): Likewise.
(after_fork): Clear `tracee->callno'.

* exec/loader-mipsel.s (rest_of_exec): Delete redundant nop.
(skip_environ): Correct stack space test.  Don't jump into
the label for the sp preserving case's delay slot.

* exec/exec.c (exec_0): Don't disable AT_EXECFN substitution on
MIPS systems.

* exec/loader-aarch64.s (skip_environ): Correct typo in
commentary.

* exec/loader-mips64el.s: Add a disclaimer that this file is
currently inoperable.

* exec/loader-mipsel.s (__start): Move environment and argument
vectors and produce and replace AT_EXECFN.  Clear stack before
proceeding to circumvent an oversight in glibc.

* exec/loader-aarch64.s (skip_environ, cleanup): Minor thinkos.

* exec/loader-x86_64.s (skip_environ): Insert missing label.

* exec/exec.c (insert_args, exec_0): On non-MIPS systems, copy
NAME and its length to the loader area.  State that MIPS support
is not yet available (though it will be pending the availability
of a functioning emulator).

* exec/loader-aarch64.s (_start):

* exec/loader-armeabi.s (_start):

* exec/loader-x86.s (_start):

* exec/loader-x86_64.s (_start): Displace auxv, environ, and
argv to create sufficient space for the provided file name, and
copy the file name there.  Replace AT_EXECFN to refer to this
space.