Make --with-pkg-config the default, i.e., by default if pkg-config is installed, then the installed examples will be built using the pkg-config approach.  This method is noticeably faster than the alternate plplot-config approach, but the plan is to also continue to maintain the alternate approach since that is necessary on systems without pkg-config installed.
Make --with-pkg-config the default, i.e., by default if pkg-config is
installed, then the installed examples will be built using the pkg-config
approach.  This method is noticeably faster than the alternate plplot-config
approach, but the plan is to also continue to maintain the alternate
approach since that is necessary on systems without pkg-config installed.

svn path=/trunk/; revision=6549

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