finch.toml, threads and atomics, finch fmt, C++ files, struct #defines, a struct variable given for its ptr

- finch.toml: name, entry, paths, include, links, libdirs, cflags, ldflags, and [target.windows] etc.;
  finch run / build / test with no file use its entry
- import thread: spawn, join, mutex, cpus; atomic_add/sub/load/store/swap/cas built in
- finch fmt [--check]: indentation by { }, trailing spaces, empty lines; also as LSP formatting
- link "x.cpp" (or in finch.toml): built with the C++ compiler, which then links (FINCH_CXX)
- #define RAYWHITE (Color){ 245, 245, 245, 255 } imports as a Color
- push(body) where push takes ptr[Body]: the same as push(addr(body))
- --target android (NDK clang from ANDROID_NDK_HOME, -llog)

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_016GzNP6r8dg6WDxUVZy8wjL

src/host.fch

@@ -81,3 +81,18 @@ fn removeTree(str path) {
 fn move(str from, str to) {
     shell("mv " + quote(from) + " " + quote(to))
 }
+
+// the files under dir (and its folders) whose names end with ext, like ".fch"
+fn listFiles(str dir, str ext) -> []str {
+    tmp := tempDir() + "/finch_files_" + str(pid()) + ".txt"
+    run("find " + quote(dir) + " -type f -name " + quote("*" + ext) + " > " + quote(tmp) + " 2> " + nullDevice())
+    text := read_file(tmp) or ""
+    remove(tmp)
+    []str out
+    for line in text.replace("\r", "").split("\n") {
+        if line.ends_with(ext) {
+            out.push(line)
+        }
+    }
+    return out
+}