Use a root of library when filtering source code using library.json and srcFilter field

HISTORY.rst

@@ -7,6 +7,9 @@ PlatformIO 3.0
 3.4.1 (2017-??-??)
 ~~~~~~~~~~~~~~~~~~
 
+* Use a root of library when filtering source code using
+  `library.json <http://docs.platformio.org/page/librarymanager/config.html>`__
+  and ``srcFilter`` field
 * Do not ask for board ID when initialize project for desktop platform
 * Fixed issue when can not load broken PIO Core state
 

platformio/builder/tools/piolib.py

@@ -521,6 +521,15 @@ class PlatformIOLibBuilder(LibBuilderBase):
     def _is_arduino_manifest(self):
         return isfile(join(self.path, "library.properties"))
 
+    @property
+    def src_dir(self):
+        if all([
+                "srcFilter" in self._manifest.get("build", {}) or
+                self.env['SRC_FILTER'], not self._is_arduino_manifest()
+        ]):
+            return self.path
+        return LibBuilderBase.src_dir.fget(self)
+
     @property
     def src_filter(self):
         if "srcFilter" in self._manifest.get("build", {}):