gnuplot: upgrade to 4.6.5

* automake patch from 4.4.4 is no longer needed
* PACKAGECONFIG for lua (lua term is only useful for LaTeX)
* linking problems with dlopen, etc. in lua loadlibs.c fixed
  ** this same problem was seen in jansa world builds for 4.4.4
  ** I am not able to replicate that error on 4.4.4

NOTE: qt is supported by this version, but I was not able to
figure out the configuration...

Signed-off-by: Tim Orling <TicoTimo@gmail.com>
Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>