Adds alias __errno to linker file fixed link, need to understand why.

CMakeLists.txt

@@ -278,7 +278,7 @@ endforeach()
 
 add_subdirectory(src/firmware/${OS})
 if (config_io_board)
-	#add_subdirectory(src/modules/px4iofirmware)
+	add_subdirectory(src/modules/px4iofirmware)
 endif()
 
 #=============================================================================

cmake/configs/nuttx_px4fmu-v2_default.cmake

@@ -174,7 +174,7 @@ set(config_extra_libs
 	)
 
 set(config_io_extra_libs
-	${CMAKE_SOURCE_DIR}/src/lib/mathlib/CMSIS/libarm_cortexM3l_math.a
+	#${CMAKE_SOURCE_DIR}/src/lib/mathlib/CMSIS/libarm_cortexM3l_math.a
 	)
 
 add_custom_target(sercon)

nuttx-configs/px4io-v2/scripts/ld.script

@@ -72,6 +72,12 @@ SECTIONS
 		*(.gcc_except_table)
 		*(.gnu.linkonce.r.*)
 		_etext = ABSOLUTE(.);
+
+		/* 
+		 * This is a hack to make the newlib libm __errno() call
+		 * use the NuttX get_errno_ptr() function.
+		 */
+		__errno = get_errno_ptr;
 	} > flash
 
 	/*

src/modules/px4iofirmware/CMakeLists.txt

@@ -110,6 +110,7 @@ add_dependencies(firmware_io_nuttx
 	nuttx_export_${config_io_board}
 	msg_gen
 	io_prebuild_targets
+	mixer_gen
 	)
 
 set(nuttx_export_dir ${CMAKE_BINARY_DIR}/${config_io_board}/NuttX/nuttx-export)

src/modules/systemlib/mixer/CMakeLists.txt

@@ -37,6 +37,9 @@ add_custom_command(OUTPUT mixer_multirotor.generated.h
 	COMMAND ${PYTHON_EXECUTABLE} ${CMAKE_CURRENT_SOURCE_DIR}/multi_tables.py
 	> mixer_multirotor.generated.h)
 
+add_custom_target(mixer_gen
+	DEPENDS mixer_multirotor.generated.h)
+
 px4_add_module(
 	MODULE modules__systemlib__mixer
 	SRCS