Define valid platform bundled libraries folder names in the platform package

Author: per1234

project/platform/platform.go

@@ -40,3 +40,17 @@ func IsRequiredConfigurationFile(filePath *paths.Path) bool {
 	}
 	return false
 }
+
+// See: https://arduino.github.io/arduino-cli/latest/platform-specification/#platform-bundled-libraries
+var bundledLibrariesFolderNames = map[string]struct{}{
+	"libraries": empty,
+}
+
+func BundledLibrariesFolderNames() []string {
+	folderNames := make([]string, 0, len(bundledLibrariesFolderNames))
+	for folderName := range bundledLibrariesFolderNames {
+		folderNames = append(folderNames, folderName)
+	}
+
+	return folderNames
+}

project/project.go

@@ -108,8 +108,10 @@ func findSubprojects(superproject Type, apexSuperprojectType projecttype.Type) [
 			immediateSubprojects = append(immediateSubprojects, findProjectsUnderPath(subprojectPath, projecttype.Sketch, true)...)
 		}
 	case projecttype.Platform:
-		subprojectPath := superproject.Path.Join("libraries")
-		immediateSubprojects = append(immediateSubprojects, findProjectsUnderPath(subprojectPath, projecttype.Library, false)...)
+		for _, subprojectFolderName := range platform.BundledLibrariesFolderNames() {
+			subprojectPath := superproject.Path.Join(subprojectFolderName)
+			immediateSubprojects = append(immediateSubprojects, findProjectsUnderPath(subprojectPath, projecttype.Library, false)...)
+		}
 	case projecttype.PackageIndex:
 		// Platform indexes don't have subprojects
 		return nil