Initial project import

tools/v/vlib/os/execute_thread_test.c.v

@@ -0,0 +1,41 @@
+import os
+
+fn execute_in_thread(id int) !string {
+	res := os.execute('printf thread_${id}')
+	if res.exit_code != 0 {
+		return error('thread ${id} failed: exit=${res.exit_code} output="${res.output.trim_space()}"')
+	}
+	return res.output
+}
+
+fn test_execute_inside_spawned_threads() {
+	$if windows {
+		return
+	}
+	$if macos {
+		// On macos-14 GitHub Actions runners, when the V repo is checked out
+		// under a path that contains non-ASCII bytes (the space-paths CI does
+		// this with `你好 my $path, @с интервали`), os.execute() inside spawned
+		// threads consistently returns empty output here, even with FD_CLOEXEC
+		// and a V-level pthread mutex serializing pipe()+posix_spawn. Regular
+		// macos CI (ASCII paths) passes the test, so skip only when the cwd
+		// contains non-ASCII bytes.
+		cwd := os.getwd()
+		for b in cwd.bytes() {
+			if b >= 0x80 {
+				return
+			}
+		}
+	}
+	for _ in 0 .. 3 {
+		mut threads := []thread !string{}
+		for i in 0 .. 4 {
+			threads << spawn execute_in_thread(i)
+		}
+		mut outputs := []string{cap: 4}
+		for t in threads {
+			outputs << t.wait() or { panic(err) }
+		}
+		assert outputs == ['thread_0', 'thread_1', 'thread_2', 'thread_3']
+	}
+}