Units (k, M, G, T, P, E) cannot be provided as variable values on command line

Units (k, M, G, T, P, E) cannot be provided as variable values on command line:

SQL> set global innodb_buffer_pool_size = 256M;
ERROR 1232 (42000): Incorrect argument type to variable 'innodb_buffer_pool_size'

SQL> set global innodb_buffer_pool_size = 256*1024*1024;
Query OK, 0 rows affected (0.000 sec)

Would be a nice goody. Some simple task for GSOC or other community contribution?