fix platform dir

Author: georgeharker

Teensy.mk

@@ -49,6 +49,12 @@ endif
 ARCHITECTURE  = $(call PARSE_TEENSY,$(BOARD_TAG),build.architecture)
 AVR_TOOLS_DIR = $(call dir_if_exists,$(ARDUINO_DIR)/hardware/tools/$(ARCHITECTURE))
 
+# define plaform lib dir ignoring teensy's oversight on putting it all in avr
+ifndef ARDUINO_PLATFORM_LIB_PATH
+    ARDUINO_PLATFORM_LIB_PATH = $(ARDUINO_DIR)/hardware/$(ARDMK_VENDOR)/avr/libraries
+    $(call show_config_variable,ARDUINO_PLATFORM_LIB_PATH,[COMPUTED],(from ARDUINO_DIR))
+endif
+
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