In the original Sconstruct script, `GetDepend('__STACKSIZE__')`
is placed before the call to `PrepareBuilding()`, which causes
the value of `GetDepend('__STACKSIZE__')` to always be False,
and the value of `__STACKSIZE__` in `link_stacksize.lds` will
not be updated.
Solution: move the call if `PrepareBuilding()` ahead.
Also sync and update the .config and rtconfig.h, plus the
link_stacksize.lds.
Signed-off-by: Chen Wang <unicorn_wang@outlook.com>
c8914c7f2b