https://gcc.gnu.org/bugzilla/show_bug.cgi?id=119213
--- Comment #10 from Iain Sandoe <iains at gcc dot gnu.org> --- In my patches for Darwin/macOS - I did it in a more long-winded way by removing the CPPFLAGS def completely and then adding: +CFLAGS-cobol/cobol1.o += -I$(LIB_SOURCE) +CFLAGS-cobol/genutil.o += -I$(LIB_SOURCE) ... etc for each of the sources that needs the library headers, including the generated ones: e.g. +CFLAGS-cobol/cdf.o += -I$(LIB_SOURCE) ==== I am not saying this is necessarily a better solution (there are more lines of code) - but it does isolate the additional include paths to only the specific files that need them. ----- As far as this PR is concerned - I'd say the more significant aspect is to remove the hard-wired library and standard settings. This is what the patch at comment #6 does.