Errors compiling

[James Rome]

On SUSE 11.1, I get:
-------------------------------------------------------------------------------
              Building crutserver for Linux (RELEASE)
-------------------------------------------------------------------------------
Compiling main.c
In file included from main.c:4:
crutserver.h:15:21: error: GL/glut.h: No such file or directory
main.c: In function ‘buildGLUTMenu’:
main.c:254: warning: implicit declaration of function ‘glutCreateMenu’
main.c:259: warning: implicit declaration of function ‘glutAddMenuEntry’
main.c:263: warning: implicit declaration of function ‘glutAddSubMenu’
main.c:266: warning: implicit declaration of function ‘glutAttachMenu’
main.c: In function ‘crutInitServer’:
main.c:321: warning: implicit declaration of function ‘glutInit’
main.c:323: error: ‘GLUT_DEPTH’ undeclared (first use in this function)
main.c:323: error: (Each undeclared identifier is reported only once
main.c:323: error: for each function it appears in.)
main.c:323: error: ‘GLUT_DOUBLE’ undeclared (first use in this function)
main.c:323: error: ‘GLUT_RGBA’ undeclared (first use in this function)
main.c:325: error: ‘GLUT_ALPHA’ undeclared (first use in this function)
main.c:327: error: ‘GLUT_STENCIL’ undeclared (first use in this function)
main.c:328: warning: implicit declaration of function ‘glutInitDisplayMode’
main.c:330: warning: implicit declaration of function ‘glutInitWindowPosition’
main.c:331: warning: implicit declaration of function ‘glutInitWindowSize’
main.c:333: warning: implicit declaration of function ‘glutCreateWindow’
main.c:335: warning: implicit declaration of function ‘glutDisplayFunc’
main.c: In function ‘main’:
main.c:451: warning: implicit declaration of function ‘glutMouseFunc’
main.c:454: warning: implicit declaration of function ‘glutKeyboardFunc’
main.c:457: warning: implicit declaration of function ‘glutMotionFunc’
main.c:460: warning: implicit declaration of function ‘glutPassiveMotionFunc’
main.c:463: warning: implicit declaration of function ‘glutVisibilityFunc’
main.c:466: warning: implicit declaration of function ‘glutReshapeFunc’
main.c:475: warning: implicit declaration of function ‘glutMainLoop’
gmake[2]: *** [../built/crutserver/Linux/main.o] Error 1
gmake[1]: *** [dep] Error 2
make: *** [crutserver.subdir] Error 2

Where is GL/glut.h?