Improve cross-platform on Windows

build/_build.ts

@@ -18,8 +18,8 @@ async function main() {
 
   // if we have an explicit bin directory, use the executables there (needed for glitch.com)
   if (fs.existsSync("bin")) {
-    process.env.PATH = __dirname + "/../bin/:" + process.env.PATH;
-    process.env.FIFTPATH = __dirname + "/../bin/fiftlib";
+    process.env.PATH = path.join(__dirname, "..", "bin") + path.delimiter + process.env.PATH;
+    process.env.FIFTPATH = path.join(__dirname, "..", "bin", "fiftlib");
   }
 
   // make sure func compiler is available

build/_setup.ts

@@ -3,8 +3,12 @@
 // We rely on this script for example to support Glitch.com (online IDE) and have it working in one click
 
 import fs from "fs";
+import path from "path";
 import child_process from "child_process";
 
+// package ton-compiler brings its own func and fift executables which interfere with the system ones
+fs.rmSync(path.join(__dirname, "..", "node_modules", "ton-compiler", "bin"), { recursive: true, force: true });
+
 // check if we're running on glitch.com (glitch is running Ubuntu 16)
 if (fs.existsSync("/app/.glitchdotcom.json")) {
   // make sure we're installed once