Also breaks user level stuff, when including <signal.h> (libc5):
/usr/include/signal.h:130: warning: `sigmask' redefined
/usr/include/asm/signal.h:174: warning: this is the location of the
previous definition
/usr/include/signal.h:69: conflicting types for `sigaddset'
/usr/include/asm/signal.h:146: previous declaration of `sigaddset'
/usr/include/signal.h:70: conflicting types for `sigdelset'
/usr/include/asm/signal.h:151: previous declaration of `sigdelset'
Alex