Log Message:
gnuplot: updated to 5.2.6

Changes in 5.2.6
NEW keyword "keyentry" places an entry in the key without actually plotting
NEW "set style boxplot medianlinewidth <lw>"
CHANGE drop non-working support for CIE/XYZ color space
CHANGE strptime ignores content read with format a/A/w/W
FIX various corner-case bugs and overruns found by fuzzing
FIX revise waitforinput in x11 terminal
FIX revise waitforinput and terminal close events in qt terminal
FIX revise waitforinput and new window events in monothreaded wxt terminal
FIX lua.trm compatibility with lua version 5.3
FIX error line reporting inside an if/else bracketed clause
FIX error in date conversion for times within a nanosecond of a year boundary