machine configs: get rid of default glibc configure arguments

no need to configure them explicitly
recreate_feed: cosmetic changes

Old version was a bit complicated and hard to follow.
Merge remote-tracking branch 'openpli3/master' into HEAD

Conflicts:
	meta-openpli/conf/machine/include/etxx00.inc
	meta-openpli/conf/machine/include/vuxxo.inc
	meta-openpli/conf/machine/include/vuxxo2.inc
	meta-openpli/conf/machine/include/xp.inc