[plt-scheme] cvs sources missing file?

I just got the cvs sources, and tried to compile (for linux) and got the 
error that the file xwSimpleP.h is missing, which it is, sure enough. 
Here's the end of the make spew...

J.
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In file included from ./XWidgets/xwMultiList.c:68:
XWidgets/xwMultiListP.h:56: X11/Xaw/SimpleP.h: No such file or directory
In file included from XWidgets/xwMultiListP.h:57,
                  from ./XWidgets/xwMultiList.c:68:
XWidgets/xwMultiList.h:56: X11/Xaw/Simple.h: No such file or directory
make[4]: *** [XWidgets/xwMultiList.o] Error 1
make[4]: Leaving directory `/home/jp/research/plt/src/wxxt/src'
make[3]: *** [all] Error 2
make[3]: Leaving directory `/home/jp/research/plt/src/wxxt/src/x'
make[2]: *** [wx_xt] Error 2
make[2]: Leaving directory `/home/jp/research/plt/src/mred'
make[1]: *** [all] Error 2
make[1]: Leaving directory `/home/jp/research/plt/src/mred'
make: *** [mr] Error 2
strat:~/research/plt/src $
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