B-3: How can I build a Mule which works on the console of a Sun?

You can do so by defining HAVE_SUN_CONSOLE in $MULE/src/config.h.

In this case the pixrect library will be used, so SunView_Programmers should have been installed. Solaris 2.0 (or later) does not support the pixrect library, so in that case you cannot use this function. SunView_Programmers is not included even in the pre-installed SunOS 4.x, so you must install it by hand.