The meaning of -Wall

[Bruce Korb]

is in the eye of the beholder.  Therefore, it seems like it is a
reasonable thing to make it configurable.  :-)  When -Wall
gets specified, a project specific, user specific and site
specific directory can be searched for warnings to be added to
or removed from the default set built into the compiler.  The
*BSD folks can ensure that such a file would contain
--no-warn-unused-whatevers.  Make it simple and easy to understand
how to configure the thing for Joe Average User.  Likely not 3.3,
but 3.4 doesn't sound too far fetched.