cmake add libuavcan as subdirectory

-move uavcan submodule to src/modules/uavcan/libuavcan
-adding libuavcan as a subdirectory simplifies inheriting all compile
flags and include paths

cmake/common/px4_base.cmake

@@ -138,8 +138,7 @@ function(px4_add_git_submodule)
 	string(REPLACE "/" "_" NAME ${PATH})
 	add_custom_command(OUTPUT ${CMAKE_BINARY_DIR}/git_${NAME}.stamp
 		WORKING_DIRECTORY ${CMAKE_SOURCE_DIR}
-		COMMAND git submodule init ${PATH}
-		COMMAND git submodule update -f ${PATH}
+		COMMAND git submodule update --init --recursive -f ${PATH}
 		COMMAND touch ${CMAKE_BINARY_DIR}/git_${NAME}.stamp
 		)
 	add_custom_target(${TARGET}
@@ -544,7 +543,6 @@ function(px4_add_common_flags)
 	endif()
 
 	set(c_warnings
-		-Wbad-function-cast
 		-Wstrict-prototypes
 		-Wmissing-prototypes
 		-Wnested-externs

cmake/configs/nuttx_px4fmu-v2_default.cmake

@@ -168,8 +168,8 @@ set(config_io_board
 
 set(config_extra_libs
 	${CMAKE_SOURCE_DIR}/src/lib/mathlib/CMSIS/libarm_cortexM4lf_math.a
-	libuavcan.a
-	libuavcan_stm32_driver.a
+	uavcan
+	uavcan_stm32_driver
 	)
 
 set(config_io_extra_libs