Add prototype for httpTweakCachability.
Add prototype for httpTweakCachability.

darcs-hash:20061228012545-4cc09-2196bcb6f7cbbf851d87ebb990802bf9b163a8a3.gz

berkley4/polipo,jech/polipo,akkakks/polipo,Android-Apps/polipo,galeksandrp/polipo,clowwindy/polipo,berkley4/polipo,akkakks/polipo,fqtools/polipo,feijilei/polipo,jech/polipo,nxtreaming/chumen,akkakks/polipo,jech/polipo,ajmgh/polipo,Android-Apps/polipo,lkraider/polipo,nxtreaming/chumen,ssb22/polipo2,ssb22/polipo2,strongwillow/polipo,toke/polipo,fqtools/polipo,Psiphon-Inc/polipo,fqtools/polipo,feijilei/polipo,ssb22/polipo2,lkraider/polipo,dxq-git/polipo,lkraider/polipo,galeksandrp/polipo,doublec/namecoin-polipo,jeromelebel/polipo,feijilei/polipo,TierraDelFuego/opilop,danchr/polipo,nxtreaming/chumen,dxq-git/polipo,strongwillow/polipo,fukusaka/polipo,dxq-git/polipo,caeies/polipo-caeies,berkley4/polipo,gorakhargosh/polipo,galeksandrp/polipo