clang becomes confused trying to determine which vm_distance_squared
constructor to use for a literal input of 0x7fffffffffffffff, even
though the size of the input requires it to be `long` and only one
constructor can take a `long`. Switch from an explicit
0x7fffffffffffffff to the symbolic constant INT64_MAX, which has the
same value, but a platform-appropriate suffix to force the compiler to
pick the right type.
For general clarity, switch some other instances of integer maximum
literals to symbolic constants of the same value.
This commit has no effect on the generated code (except for changes to
line numbers).
Reported-by: kreatordxx <https://github.com/dxx-rebirth/dxx-rebirth/pull/324>
Fixes: 17208cca79 ("Disallow int for vm_distance_squared")