Improved concurrency for key cache reassignment

into rurik.mysql.com:/home/igor/dev/mysql-4.1-0

  After merge fix

into laptop.sanja.is.com.ua:/home/bell/mysql/bk/work-collation-4.1

into narttu.mysql.fi:/my/mysql-4.1

BTREE, HASH and RTREE are not reserved symbols anymore

into laptop.sanja.is.com.ua:/home/bell/mysql/bk/work-collation-4.1

(./mysql-test-run t/rpl*.test  do same work)

into laptop.sanja.is.com.ua:/home/bell/mysql/bk/work-simple_in-4.1

code cleunup

   distribution. libedit is used by default, one needs to use
   "--with-readline" when compiling with readline instead.

uninitialized value fixed

into sinisa.nasamreza.org:/mnt/work/mysql-4.1

Barkov approved it already

into mashka.mysql.fi:/home/my/mysql-4.1

Use server character set if --default-character-set is not used
Added convert_string() for more efficient alloc+character-set convert of strings

equivalent of compile-pentium-debug but with
--enable-maintainer-mode configure option
Maybe it's worth to merge compile-mentium-debug
and compile-pentium-maintainer to a single script

into sanja.is.com.ua:/home/bell/mysql/bk/work-simple_in-4.1

into sanja.is.com.ua:/home/bell/mysql/bk/work-collation-4.1

into sanja.is.com.ua:/home/bell/mysql/bk/work-having_resolve-4.1