change main function's define

[idoth2o]

Hi.
I want use “LLVM assembly code”(createPrintModulePass(outs())) to compile “llc” command.
So, "main function" need define “GlobalValue::ExternalLinkage” at codegen.cpp

—hope output(LLVM assembly code)—
define void @main() {
entry:
…etc
}

—current output(LLVM assembly code)—
define internal void @main() {
entry:
…etc
}