xgrass complilation

Well today I made progress and I am slowly beginning to see the
end of compilation. But under src/xgrass/pixmap I get an error about

Pixmap.h: 69: Unable to find include file 'X11/Xmu/Converters.h'

This is included in a couple of other files as well in this directory.
I have looked through most of my file system without finding any clues to this
file. I tried to remove the line but some declaration are used from this
file. Do anyone have an idea how to get around this?

Lars

Lars Schylberg Email: larss@fmi.kth.se
Dept. of Geodesy and Photogrammetry
Royal Institute of Technology (KTH) Tel. +46 8 790 86 33
S-100 44 STOCKHOLM, SWEDEN Fax. +46 8 790 66 10