feat: support libc for small devices

internal/crosscompile/fetch.go

@@ -2,6 +2,7 @@ package crosscompile
 
 import (
 	"archive/tar"
+	"archive/zip"
 	"compress/gzip"
 	"fmt"
 	"io"
@@ -79,9 +80,9 @@ func checkDownloadAndExtractESPClang(platformSuffix, dir string) error {
 	return nil
 }
 
-func checkDownloadAndExtractLibc(url, dstDir, internalArchiveSrcDir string) error {
+func checkDownloadAndExtractLibc(cfg *compileLibcConfig, url, dstDir, internalArchiveSrcDir string) error {
 	// Check if already exists
-	if _, err := os.Stat(dstDir); err == nil {
+	if cfg.IsCompiled(dstDir) {
 		return nil
 	}
 
@@ -94,9 +95,10 @@ func checkDownloadAndExtractLibc(url, dstDir, internalArchiveSrcDir string) erro
 	defer releaseLock(lockFile)
 
 	// Double-check after acquiring lock
-	if _, err := os.Stat(dstDir); err == nil {
+	if cfg.IsCompiled(dstDir) {
 		return nil
 	}
+	fmt.Fprintf(os.Stderr, "%s not found in LLGO_ROOT or cache, will download and compile.\n", dstDir)
 
 	description := fmt.Sprintf("Libc %s", path.Base(url))
 
@@ -105,7 +107,7 @@ func checkDownloadAndExtractLibc(url, dstDir, internalArchiveSrcDir string) erro
 	if err := downloadAndExtractArchive(url, tempExtractDir, description); err != nil {
 		return err
 	}
-	defer os.RemoveAll(tempExtractDir)
+	// defer os.RemoveAll(tempExtractDir)
 
 	srcDir := tempExtractDir
 
@@ -182,10 +184,14 @@ func downloadAndExtractArchive(url, destDir, description string) error {
 		if err != nil {
 			return fmt.Errorf("failed to extract %s archive: %w", description, err)
 		}
+	} else if strings.HasSuffix(filename, ".zip") {
+		err := extractZip(localFile, tempDir)
+		if err != nil {
+			return fmt.Errorf("failed to extract %s archive: %w", description, err)
+		}
 	} else {
 		return fmt.Errorf("unsupported archive format: %s", filename)
 	}
-
 	// Rename temp directory to target directory
 	if err := os.Rename(tempDir, destDir); err != nil {
 		return fmt.Errorf("failed to rename directory: %w", err)
@@ -265,3 +271,44 @@ func extractTarXz(tarXzFile, dest string) error {
 	cmd := exec.Command("tar", "-xf", tarXzFile, "-C", dest)
 	return cmd.Run()
 }
+
+func extractZip(zipFile, dest string) error {
+	r, err := zip.OpenReader(zipFile)
+	if err != nil {
+		return err
+	}
+	defer r.Close()
+	decompress := func(file *zip.File) error {
+		path := filepath.Join(dest, file.Name)
+
+		if file.FileInfo().IsDir() {
+			return os.MkdirAll(path, 0700)
+		}
+
+		fs, err := file.Open()
+		if err != nil {
+			return err
+		}
+		defer fs.Close()
+
+		w, err := os.Create(path)
+		if err != nil {
+			return err
+		}
+		if _, err := io.Copy(w, fs); err != nil {
+			w.Close()
+			return err
+		}
+		if err := w.Close(); err != nil {
+			return err
+		}
+		return nil
+	}
+
+	for _, file := range r.File {
+		if err = decompress(file); err != nil {
+			break
+		}
+	}
+	return err
+}