String handling parinoia fixes.

String handling parinoia fixes.

This patch enables the compile-time checking of strings assable by means of
sizeof().  (Original code had the configure check reversed).

This is extended to all safe_strcpy() users, push_string and pull_string,
as well as the cli and srv derivitives.  There is an attempt to cap strings
at the end of the cli buffer, and clobber_region() of the speified length
(when not -1 :-).

Becouse of the way they are declared, the 'overmalloc a string' users of
safe_strcpy() have been changed to use overmalloc_safe_strcpy() (which skips
some of the checks).

This whole ball of mud worked fine, until I pulled out my 'fix' for our
statcache.  When jeremy fixes that, we should be able to get back to testing
this stuff.

This patch also includes a 'marker' of the last caller to clobber_region (ie,
the function that called pstrcpy() that called clobber_region) to assist in
debugging problems that may have smashed the stack.  This is printed at
smb_panic() time.  (Original idea and patch by metze).

It also removes some unsused functions, and #if 0's some others that are
unused but probably should be used in the near future.

For now, this patch gives us some confidence on one class of trivial parsing
error in our code.

Andrew Bartlett
(This used to be commit 31f4827acc2a2f00399a5528fc83a0dae5cebaf4)