https://gcc.gnu.org/bugzilla/show_bug.cgi?id=120449
Jakub Jelinek <jakub at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |jakub at gcc dot gnu.org --- Comment #3 from Jakub Jelinek <jakub at gcc dot gnu.org> --- With -P there are no line markers and so the compiler assumes everything is part of the main source file, i.e. nothing comes from system headers.