On 09/25/11 09:35, Bruno Haible wrote: > AC_PROG_CC_C99 should then be preferred over AC_PROG_CC_STDC. Right?
No, because one cannot safely mix AC_PROG_CC_C99 and AC_PROG_CC_STDC, just as one cannot safely mix AC_PROG_CC_STDC and AC_PROG_CC_C89, or safely mix AC_PROG_CC_C89 and AC_PROG_CC_C99. Perhaps Autoconf could be improved so that these macros can be used together, but that would require some thought: in a few places C89 is genuinely incompatible with C99, and I expect the same will be true with C1x. In the past, we've ignored this issue: thus, even though gnulib modules generally require C89 or better, gnulib doesn't invoke AC_PROG_CC_C89. On further thought, perhaps we should continue to ignore it.