For the traditional build system for the installed examples which depends on Make and pkg-config, honor the PKG_CONFIG_PATH environment variable to be more consistent with what CMake does.
For the traditional build system for the installed examples which
depends on Make and pkg-config, honor the PKG_CONFIG_PATH environment
variable to be more consistent with what CMake does.

In certain cases the previous inconsistency between what CMake found
via pkg-config and what was found by the traditional build system via
pkg-config caused build errors for the traditional build system.
Those errors have now been solved by this fix.


svn path=/trunk/; revision=12867

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