This has irritated me for a while in configure.ac. You've probably seen this pattern before:

AC_INIT([foo], [0.0.1])
MAJOR=0
MINOR=0
MICRO=1
MY_VERSION=$MAJOR.$MINOR.$MICRO
AC_SUBST(MAJOR)
AC_SUBST(MINOR)
AC_SUBST(MICRO)
AC_SUBST(MY_VERSION)

I finally hit my annoyance threshold for this, and the answer is pretty obvious. (If its not, or you think there is a simpler one, give it a shot - I'd like something more pithy).

AC_DEFUN([MAJOR], [0])
AC_DEFUN([MINOR], [0])
AC_DEFUN([MICRO], [1])
AC_DEFUN([MY_VERSION], [MAJOR.MINOR.MICRO])
AC_INIT([foo], [MY_VERSION])
AC_SUBST(MAJOR)
AC_SUBST(MINOR)
AC_SUBST(MICRO)
AC_SUBST(MY_VERSION)

Its not a big deal to be duplicating version numbers, but not duplicating at all is nicer.