how to deal with const

[perryh at pluto.rain.com]

>   If you need strstr(3) in your project is allready defined
> in libkern. The implementation is identical, but using the
> __DECONST macro.
>
>   Take a look in /usr/src/sys/libkern/strstr.c for the function 
> definition and /usr/src/sys/geom/label/g_label.c for usage.
>
>   The function prototype is defined in sys/libkern.h

There's no strstr.c in my (6.1) libkern, but sys/cdefs.h does provide
__DECONST and it certainly looks like the intended solution.  Thanks
for the pointer.