Add initial support for briki core (#294)

builder/frameworks/arduino.py

@@ -27,10 +27,17 @@ from os.path import join
 from SCons.Script import DefaultEnvironment, SConscript
 
 env = DefaultEnvironment()
+board = env.BoardConfig()
+build_core = board.get("build.core", "").lower()
 
 SConscript("_embed_files.py", exports="env")
 
-if "espidf" not in env.subst("$PIOFRAMEWORK"):
+if build_core == "mbcwb":
+    SConscript(
+        join(DefaultEnvironment().PioPlatform().get_package_dir(
+            "framework-arduino-mbcwb"), "tools", "platformio-esp-build.py"))
+
+elif "espidf" not in env.subst("$PIOFRAMEWORK"):
     SConscript(
         join(DefaultEnvironment().PioPlatform().get_package_dir(
             "framework-arduinoespressif32"), "tools", "platformio-build.py"))