Has anyone else noticed any problem with mount beginning a few days ago?  
   I rebuilt a -current kernel from the sources sup'ed on the 15h, and I now 
   get "file system not clean, use fsck(8)" for each file system that gets 
   mounted.

You will see that message every time you try to mount a file system
that doesn't have its `clean' bit set.  Normally, the `clean' bit
would be set when the file system is unmounted or downgraded to
read-only, if it was set when the file system was mounted.  You need
to install an updated fsck(8) to set the `clean' bit initially.