Will __GXX_EXPERIMENTAL_CXX0X__ go away?

[Patrick Horgan <phorgan1@xxxxxxxxx>]

I'm using the following in a header that uses typeof and needs to build
in code that builds with -std=c++0x or the default -std=c++98.  Can I
leave it and forget it, or will eventually the compiler's use of c++0x
features no longer be experimental?  How do I future proof it?

#ifdef __GXX_EXPERIMENTAL_CXX0X__
#define typeof decltype
#endif


Patrick