Suggested by John Darrington <john@darrington.wattle.id.au>.
* configure.ac: Forbid occurrences of 'PKG_CHECK_MODULES' in the
output.
guix_localstatedir="`eval echo $localstatedir | sed -e "s|NONE|/usr/local|g"`"
AC_SUBST([guix_localstatedir])
+dnl We require the pkg.m4 set of macros from pkg-config.
+dnl Make sure it's available.
+m4_pattern_forbid([PKG_CHECK_MODULES])
+
PKG_CHECK_MODULES([GUILE], [guile-2.0 >= 2.0.5])
AC_PATH_PROG([GUILE], [guile])
AC_PATH_PROG([GUILD], [guild])