Added --force option to the call of libtoolize, forcing the file ltmain.sh to be overwritten.  This is crucial when running bootstrap.sh with a new version of Libtool in a non-fresh build tree.
Added --force option to the call of libtoolize, forcing the file
ltmain.sh to be overwritten.  This is crucial when running bootstrap.sh with
a new version of Libtool in a non-fresh build tree.

svn path=/trunk/; revision=4871

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