is there any trait to check if variable is __gshared?

[ketmar]

> Why do you need it?
i need to iterate over all module variables and 'register' (read: 
generate some wrappers) only for shared and __gshared ones, 
avoiding TLS.

sure i can write a big WARNING in documentation, but i want to 
check it in compile time too.

that's kind of 'in-game command console' module and i want to be 
able to write:
mixin(CMDCON_REGISTER_VARS!modulename);
which will iterate over all module vars and 'register' in console 
those which names stars with 'cvar_' and which are either 
'shared' or '__gshared'.

sorry for the messy explanation.