Discard the EXPORT from sqAssert.h for declaring VM functions
Discard the EXPORT from sqAssert.h for declaring VM functions

If we don't need to define the EXPORT in sqVirtaulMachine.h, then we don't need it either in sqAssert.h
Otherwise, it's a recipe for creating conflicting declarations and make some compilation fail
(for example building a plugin whishing to sqAssert as SQUEAK_BUILTIN_PLUGIN)
Only keep IMPORT for the case of SQUEAK_EXTERNAL_PLUGIN.

timfel/squeakvm,timfel/squeakvm,timfel/squeakvm,timfel/squeakvm,timfel/squeakvm,timfel/squeakvm,timfel/squeakvm,timfel/squeakvm