[wmx] xnodecor - help

when i try to compile xnodecor.c i get this:

bash$ gcc -o xnodecor xnodecor.c -L/usr/X11R6/lib -I/usr/X11R6/include
-lX11
xnodecor.c: In function `main':
xnodecor.c:67: `optarg' undeclared (first use this function)
xnodecor.c:67: (Each undeclared identifier is reported only once
xnodecor.c:67: for each function it appears in.)
xnodecor.c:95: `optind' undeclared (first use this function)

----
what am i doing wrong ? and where this opt**  come from ?

cheers
g