解决方法
GCC 4.6对C1X功能有一些实验支持：
There is now experimental support for some features from the upcoming C1X revision of the ISO C standard. This support may be selected with -std=c1x,or -std=gnu1x for C1X with GNU extensions. Note that this support is experimental and may change incompatibly in future releases for consistency with changes to the C1X standard draft. The following features are newly supported as described in the N1539 draft of C1X (with changes agreed at the March 2011 WG14 meeting); some other features were already supported with no compiler changes being needed,or have some support but not in full accord with N1539 (as amended).
- Static assertions (_Static_assert keyword)
- Typedef redefinition
- New macros in <float.h>
- Anonymous structures and unions
