Use the correct library when a relative path is passed as --library value

Author: MatteoPologruto

commands/compile/compile.go

@@ -128,7 +128,12 @@ func Compile(ctx context.Context, req *rpc.CompileRequest, outStream, errStream
 	// FIXME: This will be redundant when arduino-builder will be part of the cli
 	builderCtx.OtherLibrariesDirs = paths.NewPathList(req.GetLibraries()...)
 	builderCtx.OtherLibrariesDirs.Add(configuration.LibrariesDir(configuration.Settings))
-	builderCtx.LibraryDirs = paths.NewPathList(req.Library...)
+	for _, libPath := range paths.NewPathList(req.Library...) {
+		if libPath, err = libPath.Abs(); err != nil {
+			return nil, &arduino.LibraryNotFoundError{Cause: err}
+		}
+		builderCtx.LibraryDirs = append(builderCtx.LibraryDirs, libPath)
+	}
 	if req.GetBuildPath() == "" {
 		builderCtx.BuildPath = sk.DefaultBuildPath()
 	} else {