Newer autoconf versions (from 2.60) want a 'datarootdir' definition in

(Make-)files that use mandir (and other data directory macros).

This patch solves a warning during configure, specifically:

...
config.status: creating Makefile.pre
config.status: WARNING:  ../Makefile.pre.in seems to ignore the --datarootdir setting
...

See also: <http://www.gnu.org/software/automake/manual/autoconf/Changed-Directory-Variables.html>

Makefile.pre.in

@@ -82,6 +82,9 @@ prefix=		@prefix@
 # Install prefix for architecture-dependent files
 exec_prefix=	@exec_prefix@
 
+# Install prefix for data files
+datarootdir=    @datarootdir@
+
 # Expanded directories
 BINDIR=		$(exec_prefix)/bin
 LIBDIR=		$(exec_prefix)/lib