selectively increase optimization -Os -> -O2

- targetted at modules/libraries that benefit without drastically
increasing flash usage
 - ignored on boards with CONSTRAINED_FLASH set

platforms/nuttx/src/px4/common/CMakeLists.txt

@@ -32,7 +32,7 @@
 ############################################################################
 
 # skip for px4_layer support on an IO board
-if (NOT ${PX4_BOARD} MATCHES "px4_io")
+if(NOT PX4_BOARD MATCHES "px4_io")
 
 	add_library(px4_layer
 		board_crashdump.c

platforms/nuttx/src/px4/stm/stm32_common/dshot/CMakeLists.txt

@@ -34,3 +34,4 @@
 px4_add_library(arch_dshot
 	dshot.c
 )
+target_compile_options(arch_dshot PRIVATE ${MAX_CUSTOM_OPT_LEVEL})

platforms/nuttx/src/px4/stm/stm32_common/hrt/CMakeLists.txt

@@ -34,5 +34,8 @@
 px4_add_library(arch_hrt
 	hrt.c
 )
-target_compile_options(arch_hrt PRIVATE -Wno-cast-align) # TODO: fix and enable
-
+target_compile_options(arch_hrt
+	PRIVATE
+		${MAX_CUSTOM_OPT_LEVEL}
+		-Wno-cast-align # TODO: fix and enable
+)

platforms/nuttx/src/px4/stm/stm32_common/io_pins/CMakeLists.txt

@@ -32,8 +32,9 @@
 ############################################################################
 
 px4_add_library(arch_io_pins
+	input_capture.c
 	io_timer.c
 	pwm_servo.c
 	pwm_trigger.c
-	input_capture.c
 )
+target_compile_options(arch_io_pins PRIVATE ${MAX_CUSTOM_OPT_LEVEL})

platforms/nuttx/src/px4/stm/stm32_common/spi/CMakeLists.txt

@@ -34,3 +34,4 @@
 px4_add_library(arch_spi
 	spi.cpp
 )
+target_compile_options(arch_spi PRIVATE ${MAX_CUSTOM_OPT_LEVEL})