truss: fix handling of 64-bit arguments/return values for compat32

[arichardson]

Summary

Deciding whether to combine two values to a 64-bit one should be based on
the process ABI, and not dependent on whether truss is compiled for an
LP64 ABI. This is a follow-up cleanup for D27625. I found this while
looking for uses of the __LP64__ macro (since using this is wrong for
CHERI systems).

Test Plan

still works. Since I tested on AMD64 and all syscalls in the trace have their quad argument last there was no difference in the output. Should fix output for compat32 on MIPS64 though.

[arichardson]

ping?

[arichardson]

ping? I'd like to include this commit when I update https://github.com/CTSRD-CHERI/cheribsd/pull/692

[jhb]

usr.bin/truss/syscalls.c

1916

I think you can safely axe this comment.

1929

We don't use the PRI macros in FreeBSD. Typically we use '%j' and cast to uintmax_t instead.

[arichardson]

address feedback

[arichardson]

clang-format