CVS build fails on Ubuntu 14.04 i386

[flapane <int...@gm...>]

Configure summary: http://pastebin.com/chvuWVRM

Compiling error:
----------------------
/usr/bin/ld: wxterminal/wxt_gui.o: undefined reference to symbol 
'XInitThreads'
//usr/lib/i386-linux-gnu/libX11.so.6: error adding symbols: DSO missing 
from command line
collect2: error: ld returned 1 exit status
make[4]: *** [gnuplot] Errore 1
make[4]: uscita dalla directory "/home/flapane/.svnflap/gnuplot/src"
make[3]: *** [all-recursive] Errore 1
make[3]: uscita dalla directory "/home/flapane/.svnflap/gnuplot/src"
make[2]: *** [all] Errore 2
make[2]: uscita dalla directory "/home/flapane/.svnflap/gnuplot/src"
make[1]: *** [all-recursive] Errore 1
make[1]: uscita dalla directory "/home/flapane/.svnflap/gnuplot"
make: *** [all] Errore 2
----------------------