[Bug libfortran/83097] Use __BYTE_ORDER__ instead of runtime test

[jb at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83097

Janne Blomqvist <jb at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |jb at gcc dot gnu.org

--- Comment #3 from Janne Blomqvist <jb at gcc dot gnu.org> ---
We now use __BYTE_ORDER__. Leaving this PR open as a reminder to optimize
memcmp_char4.