src: fix --build-sea default executable path

src/node_sea_bin.cc

@@ -388,7 +388,7 @@ ExitCode BuildSingleExecutable(const std::string& sea_config_path,
 
   SeaConfig config = opt_config.value();
   if (config.executable_path.empty()) {
-    config.executable_path = args[0];
+    config.executable_path = Environment::GetExecPath(args);
   }
 
   // Get file permissions from source executable to copy over later.

test/sea/test-build-sea-custom-argv0.js

@@ -0,0 +1,34 @@
+'use strict';
+// This tests --build-sea with a custom argv0 value.
+
+require('../common');
+
+const { skipIfBuildSEAIsNotSupported } = require('../common/sea');
+
+skipIfBuildSEAIsNotSupported();
+
+const tmpdir = require('../common/tmpdir');
+const fixtures = require('../common/fixtures');
+const { copyFileSync } = require('fs');
+
+const { spawnSyncAndAssert } = require('../common/child_process');
+tmpdir.refresh();
+
+copyFileSync(
+  fixtures.path('sea-config.json'),
+  tmpdir.resolve('sea-config.json'),
+);
+
+copyFileSync(
+  fixtures.path('sea.js'),
+  tmpdir.resolve('sea.js'),
+);
+
+spawnSyncAndAssert(
+  process.execPath,
+  ['--build-sea', tmpdir.resolve('sea-config.json')], {
+    cwd: tmpdir.path,
+    argv0: 'argv0',
+  }, {
+    stdout: /Generated single executable/,
+  });