Replying to https://lists.gnu.org/archive/html/autoconf/2022-08/msg00006.html : > > will quietly bump its minimum C compiler requirement to C99. Are we > > okay with that? > Yes, I think so. I believe Gawk was the last Gnulib-using project that wanted > portability to C89, and Gawk dropped that requirement a few years ago. I think so too. A lot of Gnulib code nowadays requires C99 (namely, the statement-after-declaration syntax support), and we haven't heard problems with that for ca. 4-5 years. The last compiler I used with did not have it was 'cc' on IRIX 6.5. > > apparently there exist(ed?) compilers that provide _Bool but > > not stdbool.h. > Apparently OS X had that problem as recently as 2018 > <https://github.com/carp-lang/Carp/issues/332> so I guess such a > workaround would be helpful for some apps. I'm not sure Gnulib will > need it though. Bruno would know better than I. I think the user who reported <https://github.com/carp-lang/Carp/issues/332> simply did not have the appropriate -I options in his clang installation. On macOS, the include files are organized in complex hierarchies, and if you don't use the compiler driver provided by Apple, you need to add various -I and -L options. Most likely, compilers that are not older than 15 years and that have _Bool also have <stdbool.h>. Gnulib's stdbool.in.h has a couple of workarounds for older compilers, but these are not relevant any more nowadays. Bruno
