configure.ac: use AC_HEADER_MAJOR to detect major()/minor()

configure.ac: use AC_HEADER_MAJOR to detect major()/minor()

This change slightly updates c4d7f66c12853b9575366dd9f4a7960ec5694934
which added <sys/sysmacros.h> inclusion.

Autoconf has AC_HEADER_MAJOR to find out which header defines
reqiured macros:
    https://www.gnu.org/software/autoconf/manual/autoconf-2.69/html_node/Particular-Headers.html

This change should increase portability across other libcs.

Bug: https://bugs.gentoo.org/610652
Signed-off-by: Sergei Trofimovich <slyfox@gentoo.org>
Reviewed-by: Daniel Stone <daniels@collabora.com>