Sync betaflight to Gitea

mk/dronecan.mk

@@ -0,0 +1,27 @@
+# DroneCAN stack + libcanard transport.
+#
+# Each MCU family that wants the stack opts in from its own .mk file with
+# one line:
+#
+#   LIB_SUBMODULES += $(DRONECAN_LIB_DIR)
+#
+# When this file is sourced (after the MCU .mk has populated
+# LIB_SUBMODULES) the presence of that path triggers the rest of the
+# wiring: source list, size-optimised flags and include directory. MCUs
+# that don't opt in never reference libcanard, so neither the external
+# library nor the Betaflight-side glue is compiled for non-CAN targets.
+
+ifneq ($(filter $(DRONECAN_LIB_DIR),$(LIB_SUBMODULES)),)
+
+MCU_COMMON_SRC += \
+            io/dronecan/dronecan.c \
+            io/dronecan/dronecan_gnss.c \
+            io/dronecan/dronecan_node.c \
+            dronecan/libcanard/canard.c
+
+SIZE_OPTIMISED_SRC += \
+            dronecan/libcanard/canard.c
+
+INCLUDE_DIRS       += $(ROOT)/$(DRONECAN_LIB_DIR)
+
+endif