https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107008
--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> ---
In theory the existing per-target error_constants.h allows an out-of-tree port
for a new OS to use its own error_constants.h more easily. Meh. They would
still need to edit configure.host to overrride ${error_constants_dir}, so they
can just edit the error_constants.h file instead. Adding a couple of #ifdef
conditions in there seems easier than providing a whole new file anyway.
