Added prefix option.  Now all args may be preceded by any number of dashes, so that configure could look more like GNU autoconf's configure. Help message modified to reflect this.  Flags reordered alphabetically so that adding a new one/finding old ones isn't quite so haphazard.
Added prefix option.  Now all args may be preceded by any number of
dashes, so that configure could look more like GNU autoconf's configure.
Help message modified to reflect this.  Flags reordered alphabetically
so that adding a new one/finding old ones isn't quite so haphazard.

svn path=/trunk/; revision=916

FreeScienceCommunity/PLPlot,FreeScienceCommunity/PLPlot,FreeScienceCommunity/PLPlot,FreeScienceCommunity/PLPlot,FreeScienceCommunity/PLPlot,FreeScienceCommunity/PLPlot,FreeScienceCommunity/PLPlot,FreeScienceCommunity/PLPlot,FreeScienceCommunity/PLPlot