	* configure.ac: use the new XT_ARG_WITH macro of autoxt.m4. Saves 	lots of code.
	* configure.ac: use the new XT_ARG_WITH macro of autoxt.m4. Saves
	lots of code.

	* configure.ac: new autoxt.m4 requires Autoconf 2.58. This
	requirement is now checked with AC_PREREQ.

svn path=/trunk/StrategoXT/; revision=7512

metaborg/strategoxt,Apanatshka/strategoxt,lichtemo/strategoxt,lichtemo/strategoxt,metaborg/strategoxt,Apanatshka/strategoxt,Apanatshka/strategoxt,metaborg/strategoxt,Apanatshka/strategoxt,metaborg/strategoxt,metaborg/strategoxt,lichtemo/strategoxt,lichtemo/strategoxt,Apanatshka/strategoxt,lichtemo/strategoxt