[jnc_ct] changed the implementation of Module::mapVariable
[jnc_ct] changed the implementation of Module::mapVariable

apparently, with MCJIT it's not enough to barely call
llvm::ExecutionEngine::addGlobalMapping -- llvm::GlobalVariable must
have llvm::GlobalVariable::ExternalWeakLinkage (which, obviously, we
can't use as default)

therfore, during variable mapping, we create a new GlobalVariable with
proper linkage and replace the original value with it

vovkos/jancy,vovkos/jancy,vovkos/jancy,vovkos/jancy,vovkos/jancy