unvis.c doesn't compile on i386

[Kurt Schreiner <ks%ub.uni-mainz.de@localhost>]

Hi,

with -current source updated some minutes ago build.sh ... distribution
(on MacOSX) for i386 fails with:

      build  libc/libc.a
/u/NetBSD/src/lib/libc/gen/unvis.c(426): warning: bitwise operation on signed 
value possibly nonportable [117]
--- unvis.ln ---
*** [unvis.ln] Error code 1

nbmake: stopped in /u/NetBSD/src/lib/libc

(Compiles w/o problem on amd64...)

Kurt