Translate bootstrapping main from C to LLVM IR

This avoids needing a C compiler for every platform.

src/runtime/runtime.ll

@@ -0,0 +1,10 @@
+source_filename = "runtime/runtime.ll"
+
+declare void @runtime.initAll()
+declare void @main.main()
+
+define i32 @main() {
+	call void @runtime.initAll()
+	call void @main.main()
+	ret i32 0
+}