> On 20 Aug 2020, at 10:02, Torbjörn Granlund <tg at gmplib.org> wrote: > > on a Mac: > > $ cc -v It seems 'cc' is no longer in the POSIX specification, instead there is 'c99' [1]. On MacOS 10.15, 'c99 -v' says the option is illegal. 1. https://pubs.opengroup.org/onlinepubs/9699919799/utilities/c99.html