[Bug preprocessor/67551] Preprocessor generates non-ISO line directives
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67551 --- Comment #2 from Andrew Pinski --- You can also use -P to get rid of the line markers from the processor output which avoids your warning.
[Bug preprocessor/67551] Preprocessor generates non-ISO line directives
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67551 --- Comment #1 from Andrew Pinski --- Or you could use -fpreprocessed as another option which is the same as doing .i.