[Bug libstdc++/87744] Some valid instantiations of linear_congruential_engine produce compiler errors when __int128 isn't available

[redi at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87744

--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> ---
Created attachment 57345
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=57345&action=edit
Use 64-bit integers to do 128-bit arithmetic

This patch defines a custom type that implements the necessary 128-bit
arithmetic for linear_congruential_engine<uint64_t, ...> without __int128.

It's an order of magnitude slower than using __int128 natively on x86_64, but
it gives the right results.