New m4 release was made after a long time, for us most importantly
it ships newer gnulib so it compiles against GCC15 without forcing GNU17.
* Noteworthy changes in release 1.4.20 (2025-05-10) [stable]
** Fix a bug in the `eval' builtin where it does not suppress warnings
about division by zero that occurs within a more complex expression on
the right hand side of || or && (present since short-circuiting was
introduced in 1.4.8b).
** The `syscmd' and `esyscmd' builtins no longer mishandle a command line
starting with `-' or `+' (present since "the beginning").
** Fix regression introduced in 1.4.19 where trace output (such as with
`debugmode(t)') could read invalid memory when tracing a series of
pushed macros that are popped during argument collection.
** Fix regression introduced in 1.4.19 where the `format' builtin
inadvertently took on locale-dependent parsing and output of floating
point numbers as a side-effect of introducing message translations.
While it would be nice for m4 to be fully locale-aware, such a behavior
change belongs in a major version release such as 1.6, and not a minor
release.
** Fix regression introduced in 1.4.11 where the experimental `changeword'
builtin could cause a crash if given a regex that does not match all
one-byte prefixes of valid longer matches. As a reminder, `changeword'
is not recommended for production use, and will likely not be present
in the next major version release.
** On non-Unix platforms where binary files differ from text, loading a
frozen file (which should be cross-platform compatible) now correctly
uses binary mode.
** Several documentation improvements to the manual.
** Update to comply with newer C standards, and inherit portability
improvements from gnulib.
Link: https://github.com/openwrt/openwrt/pull/18821
Signed-off-by: Robert Marko <robimarko@gmail.com>
4dc10ec711