Stop using source code in build file

Signed-off-by: Sebastian Malton <sebastian@malton.name>

build/download_binaries.ts

@@ -15,8 +15,8 @@ import type { SingleBar } from "cli-progress";
 import { MultiBar } from "cli-progress";
 import { extract } from "tar-stream";
 import gunzip from "gunzip-maybe";
-import { getBinaryName } from "../src/common/vars";
 import { isErrnoException, setTimeoutFor } from "../src/common/utils";
+import AbortController from "abort-controller";
 
 type Response = FetchModule.Response;
 type RequestInfo = FetchModule.RequestInfo;
@@ -24,6 +24,14 @@ type RequestInit = FetchModule.RequestInit;
 
 const pipeline = promisify(_pipeline);
 
+const getBinaryName = (binaryName: string, { forPlatform }: { forPlatform : string }) => {
+  if (forPlatform === "windows") {
+    return `${binaryName}.exe`;
+  }
+
+  return binaryName;
+};
+
 interface BinaryDownloaderArgs {
   readonly version: string;
   readonly platform: SupportedPlatform;