Don't print the entire declaration of the alliassee when `->toChars()` is called on an `AliasDeclaration`; just printing the name will do. This fixes #305, which otherwise tries to generate {{{ class E { void A() { alias /* recurse into E->toCBuffer() */ m; } } }}} by way of an infinite recursion (causing a segfault when the stack runs out).

#ifndef LDC_GEN_OPTIMIZER_H
#define LDC_GEN_OPTIMIZER_H

namespace llvm { class Module; }

bool ldc_optimize_module(llvm::Module* m);

bool doInline();

int optLevel();

bool optimize();

#endif