5.1+ specific fixes (plugins etc.)


include/my_getopt.h:
  make both ull and ll global
mysql-test/r/index_merge_myisam.result:
  we throw warnings to the client, yea, verily
mysql-test/r/innodb.result:
  we throw warnings to the client, yea, verily
mysql-test/r/variables.result:
  we throw warnings to the client, yea, verily
mysql-test/t/variables.test:
  correct result, is multiple of variable's block_size now
mysys/my_getopt.c:
  export getopt_ll_limit_value(), check for integer wrap-around
  in it, same as in ull variant.  Only print warnings to reporter
  when caller didn't ask for diagnostics, otherwise assume caller
  will handle any warnings (id est, throw them client-wards)
sql/mysqld.cc:
  correct signedness of "concurrent-insert"
sql/sql_plugin.cc:
  Throw sys-var out-of-range warnings client-wards for
  plugins, too.