[Bug preprocessor/64864] [5 Regression] preprocessor linemarkers break configure checks

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64864

--- Comment #2 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
I really think this is porting_to.html material, rather than a bug report.