** Backward incompatibilities
*** AC_CHECK_FUNC and similar macros now use function prototypes.
- AC_CHECK_FUNC and and similar macros now use C declarations with
- function prototypes, a feature introduced in C89. The new approach
- should work better with C23, which removed the non-prototyped K&R
+ This should work better with C23, which removed the non-prototyped K&R
style that AC_CHECK_FUNC previously used. However, this change
means Autoconf no longer supports pre-1989 C compilers, as they do
not support function prototypes.