https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81615
--- Comment #15 from Steve Kargl <sgk at troutmask dot apl.washington.edu> --- On Sat, Dec 10, 2022 at 01:47:44AM +0000, barrowes at alum dot mit.edu wrote: > > Thanks for engaging, and thanks for the suggestion. I might be able to do this > over the winter. Could you give me a hint as to where to look. Which files. > I suspect that you should start by understand gcc/fortran/lang-specs.h. That's where most of the the filename suffixes are defined. In particular, this chuck of code /* Identical to gcc.cc (cpp_options), but omitting %(cpp_unique_options) and -fpch-preprocess on -save-temps. */ #define CPP_ONLY_OPTIONS "%1 %{m*} %{f*} %{g*:%{!g0:%{g*} \ %{!fno-working-directory:-fworking-directory}}} \ %{std*&ansi&trigraphs} %{W*&pedantic*} %{w} \ %{O*} %{undef}"