https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106529
--- Comment #7 from Jonathan Wakely <redi at gcc dot gnu.org> --- (In reply to Thomas Klausner from comment #4) > a) there is no conflict since there is no builtin or otherwise sincos() > function > b) it is not declared in math.h As it says, it's a built-in function automatically recognized by GCC, which is documented here: https://gcc.gnu.org/onlinedocs/gcc/Other-Builtins.html With -std=c17 instead of the -std=gnu17 default that doesn't happen. The warning is correct, GCC gives that special handling. You can use -fno-builtin-sincos to disable the handling for this particular function, but maybe that should be the default on NetBSD. > the linker warning is correct though :) Error, not warning :)
