xgrass compile error

I got the following error when I compiled xgrass on a Sparc10 w/ sun4.1.3,
X11R5 and Motif.

/data/Grass4.1/src/xgrass/libes/Xgi
  make -f OBJ/make.rules

rm -f OBJ/Matrix.o
cc -O -D_NO_PROTO -L/usr/include -L/usr/include -I/data/Grass4.1/src/include -c Matrix.c
/data/Grass4.1/src/include/Matrix.h: 121: XmRStringArray redefined
"/data/Grass4.1/src/include/MatrixP.h", line 252: syntax error at or near variable name "XmManagerClassPart"
"/data/Grass4.1/src/include/MatrixP.h", line 415: syntax error at or near variable name "XmManagerPart"
"Matrix.c", line 75: matrix undefined
"Matrix.c", line 153: warning: undeclared initializer name XmManagerRec
"Matrix.c", line 153: syntax error at or near symbol )
"Matrix.c", line 154: syntax error at or near type word "char"
"Matrix.c", line 486: warning: undeclared initializer name xmManagerClassRec
"Matrix.c", line 547: too many initializers
"Matrix.c", line 548: too many initializers