Reuse archiveCompiledFiles helper for long commandline shrink

Since archiveCompiledFiles already handles hot cache correctly, this avoids objs.a being rebuilt even if files don't change.

Would be ideal if PathList could expose a generic Filter API (to get rid of the "duplicated" filter)

internal/arduino/builder/linker.go

@@ -22,6 +22,16 @@ import (
 	"github.com/arduino/go-paths-helper"
 )
 
+func filter(p *paths.PathList, filter func(*paths.Path) bool) paths.PathList {
+	res := (*p)[:0]
+	for _, path := range *p {
+		if filter(path) {
+			res = append(res, path)
+		}
+	}
+	return res
+}
+
 // link fixdoc
 func (b *Builder) link() error {
 	if b.onlyUpdateCompilationDatabase {
@@ -53,31 +63,16 @@ func (b *Builder) link() error {
 		// it may happen that a subdir/spi.o inside the archive may be overwritten by a anotherdir/spi.o
 		// because thery are both named spi.o.
 
-		properties := b.buildProperties.Clone()
 		archives := paths.NewPathList()
+
 		for _, object := range objectFiles {
-			if object.HasSuffix(".a") {
-				archives.Add(object)
-				continue
-			}
 			archive := object.Parent().Join("objs.a")
-			if !archives.Contains(archive) {
-				archives.Add(archive)
-				// Cleanup old archives
-				_ = archive.Remove()
-			}
-			properties.Set("archive_file", archive.Base())
-			properties.SetPath("archive_file_path", archive)
-			properties.SetPath("object_file", object)
-
-			command, err := b.prepareCommandForRecipe(properties, "recipe.ar.pattern", false)
-			if err != nil {
-				return err
-			}
-
-			if err := b.execCommand(command); err != nil {
-				return err
-			}
+			archives.AddIfMissing(archive)
+		}
+
+		for _, archive := range archives {
+			relatedObjectFiles := filter(&objectFiles, func(object *paths.Path) bool { return object.Parent().EquivalentTo(archive.Parent()) })
+			b.archiveCompiledFiles(archive.Parent(), paths.New(archive.Base()), relatedObjectFiles)
 		}
 
 		objectFileList = strings.Join(f.Map(archives.AsStrings(), wrapWithDoubleQuotes), " ")