diff --git a/platformio/builder/main.py b/platformio/builder/main.py
index a710aefc..d45e16cb 100644
--- a/platformio/builder/main.py
+++ b/platformio/builder/main.py
@@ -74,6 +74,7 @@ DEFAULT_ENV_OPTIONS = dict(
     variables=commonvars,
 
     # Propagating External Environment
+    PIOVARIABLES=commonvars.keys(),
     ENV=environ,
     UNIX_TIME=int(time()),
     PROGNAME="program",
diff --git a/platformio/builder/tools/pioplatform.py b/platformio/builder/tools/pioplatform.py
index 2c4d9184..da15af18 100644
--- a/platformio/builder/tools/pioplatform.py
+++ b/platformio/builder/tools/pioplatform.py
@@ -30,10 +30,9 @@ def initPioPlatform(name):
 
 def PioPlatform(env):
     variables = {}
-    for key in ("board", "pioframework"):
-        if key.upper() not in env:
-            continue
-        variables[key] = env[key.upper()]
+    for name in env['PIOVARIABLES']:
+        if name in env:
+            variables[name.lower()] = env[name]
     p = initPioPlatform(env['PLATFORM_MANIFEST'])
     p.configure_default_packages(variables, COMMAND_LINE_TARGETS)
     return p