prototypes-fixes-20020821

prototypes-fixes-20020821

add externs removed and missed

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This delta was composed from multiple commits as part of the CVS->Git migration.
The checkin message with each commit was inconsistent.
The following are the additional commit messages.
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ok, another try. don't include protosw.h here and let sysincludes.h pull it in

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one more missed extern

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keep trying...

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fix weird redefintion problem with kmem_alloc

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can't know this sort of thing (and it's wrong at least sometimes)