https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116757
--- Comment #2 from Sam James <sjames at gcc dot gnu.org> --- Looking at r10-7943-g3685c5adf5c0b3, it was introduced to solve a general "no FS support" case, not broken tmpnam/fopen/whatever, so we can drop tmpnam in theory. mkstemp is maybe too new (lol) but the program isn't executed, so can't we just hardcode some path instead?
