Problem with MSYS2 build: AC_PROG_CC_C99 is obsolete (also printf attribute is printf-dependent)

Because I was feeling the need to upgrade OpenSSL, I decided to make a rebuild of my 0.4.5.7 binary.
Update of OpenSSL in MSYS2 usually done with single command: pacman -Syuu.
This time there was a problem with GPG keys.
After solving it, I found that Tor fails to build:

Vort@Vort-PC MINGW64 /e/_Projects/_Test/tor
$ ./autogen.sh && ./configure --disable-unittests --disable-asciidoc --disable-module-dirauth && make
/usr/bin/autoreconf
configure.ac:444: warning: The macro `AC_PROG_CC_C99' is obsolete.
configure.ac:444: You should run autoupdate.
../autoconf-2.71/lib/autoconf/c.m4:1659: AC_PROG_CC_C99 is expanded from...
configure.ac:444: the top level
autoreconf: error: /usr/bin/autoconf failed with exit status: 1

Removing of AC_PROG_CC_C99 line from configure.ac solved this particular problem, but I think that maybe more correct solutions exists.
Also buildlog was flooded with format-related messages like this:

src/lib/wallclock/time_to_tm.c:108:27: warning: too many arguments for format [-Wformat-extra-args]

Maybe it should be addressed too.