Fix the build script

build.js

@@ -66,6 +66,8 @@ async function opt(input, output, optflags, cwd) {
 }
 
 const srcs = [
+  'zlib-exports',
+
   'zlib/adler32',
   'zlib/compress',
   'zlib/crc32',
@@ -81,7 +83,6 @@ const srcs = [
   'zlib/trees',
   'zlib/uncompr',
   'zlib/zutil',
-  'zlib-exports',
 ];
 
 (async () => {

src/include/stdio.h

@@ -3,5 +3,4 @@
 #include <stddef.h>
 
 int snprintf(char *, size_t, const char *, ...);
-int vsnprintf(char *, size_t, const char *, ...);
-int vsnprintf(char *, size_t, const char *, ...);
+int vsnprintf(char *, size_t, const char *, __builtin_va_list);

src/zlib-exports.c

+#include <webassembly.h>
 #include <stdlib.h>
 
 #include "import.h"
+
+export int add2(int a, int b) {
+    return a + b;
+}

test.js

+const assert = require('assert');
+const wasm = require('webassembly');
+
+(async () => {
+  const zlib = await wasm.load(`${__dirname}/build/zlib.wasm`);
+
+  assert.strictEqual(zlib.exports.add2(8, 5), 13);
+})();