kernel/idle: fix rt_thread_idle_excute in high optimization level

The rt_list_isempty has prototype of "int rt_list_isempty(const rt_list_t *l)".
So the compiler has a good reason that the rt_thread_defunct list does
not change within rt_thread_idle_excute thus optimize the "while" loop
into a "if".

So add the volatile qualifier when test against the rt_thread_defunc list.
Merge pull request #336 from grissiom/fix-idle

kernel/idle: fix rt_thread_idle_excute in high optimization level
Remove unsupport syntex for python 2.6.

Dict Comprehensions is imported in Python 2.7 & 3.0 which is PEP 274 [1]. Some
OS like CentOS 6 which is use Python 2.6 cannot support this syntex.

[1] http://legacy.python.org/dev/peps/pep-0274/

Signed-off-by: Xiongfei Guo <xfguo@credosemi.com>
Merge pull request #337 from xfguo/ignore-pep274

Remove unsupport syntex for python 2.6.
update RW009 driver.
Merge pull request #338 from aozima/pulls

update RW009 driver.
拼写错误

drvers->drivers
Merge branch 'master' of https://github.com/RT-Thread/rt-thread
[shell] Fix compiling issue when DFS is not enable
[Kernel] comments clean up.
[libcpu] Add builtin ffs implementation for Cortex-M4.
[Kernel] comments clean up.
[LogTrace] Use OFLAG_RDWR to replace FLAG_RDWR when opening a device.
[Kernel] Use stream mode to open console device.
Merge branch 'master' of https://github.com/RT-Thread/rt-thread
Merge pull request #339 from tcz717/patch-1

[bsp] Fix the spelling errors.
[Ymodem]When active end the session, It can config send CAN number.
[Ymodem]Add device open flag as input parameter to ymodem function.
[BSP]Fixes two writing mistake for stm32f10x.
[BSP]Add serial receive overflow interrupt to stm32f10x ISR.