
Reintroduced the test for emptiness of $2 in the definition of macro
CHECK_PROG.  This will hopefully fix the "empty for list" problem.

svn path=/trunk/; revision=4708

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