SWEB no longer compiles with GCC 13

[Ferdi265]

GCC 13 will break SWEB again: GCC 13 Changelog

• support for STABS will be removed
  (this breaks some debug info stuff still used by x86_32 and arm targets; this would require porting over to DWARF debug info, if STABS is still used there)
• GCC now supports __is_convertible as a builtin
  (this breaks <ustl/uttraits.h>, but is easily fixed by using the code path already used for clang)

Tested with GCC snapshot builds from here: https://jwakely.github.io/pkg-gcc-latest/

[Woazboat]

STABS is already deprecated since at least 12 afaik? (Which already caused SWEB compilation to fail due to Werror)

Haven't tested with GCC 13, but those problems should be fixed by #287 by switching to DWARF and replacing the ustl.

[Ferdi265]

That sounds great!

The quick fix with ustl is mainly stated here for completeness and for students of the current semester that develop on Arch, Fedora, or OpenSUSE Tumbleweed, which will probably get GCC 13 soon.

[Woazboat]

I created a PR with a fix for the builtin in the meantime