Fix issue when development platform doesn't support frameworks

platformio/builder/tools/piomisc.py

@@ -17,8 +17,8 @@ from __future__ import absolute_import
 import atexit
 import re
 from glob import glob
-from os import environ, listdir, remove
-from os.path import isdir, isfile, join
+from os import environ, remove
+from os.path import isfile, join
 
 from platformio import util
 

platformio/managers/platform.py

@@ -461,6 +461,8 @@ class PlatformBase(PlatformPackagesMixin, PlatformRunMixin):
     def configure_default_packages(self, variables, targets):
         # enbale used frameworks
         for framework in variables.get("framework", "").split(","):
+            if not self.frameworks:
+                continue
             framework = framework.lower().strip()
             if not framework or framework not in self.frameworks:
                 continue