build/SConstruct:
Add 'default=' argument to specify base config to use when setting
up a new build dir with a different name, e.g.:
scons default=ALPHA_SE USE_MYSQL=no ALPHA_SE_NOSQL/m5.opt
--HG--
extra : convert_revision : 0f7ee1414b3e84b36114415182baf54a8adab9b7