selectively increase optimization -Os -> -O2

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

src/lib/drivers/accelerometer/CMakeLists.txt

@@ -35,9 +35,5 @@ px4_add_library(drivers_accelerometer
 	PX4Accelerometer.cpp
 	PX4Accelerometer.hpp
 )
-target_link_libraries(drivers_accelerometer
-	PRIVATE
-		conversion
-		drivers__device
-		mathlib
-)
+target_compile_options(drivers_accelerometer PRIVATE ${MAX_CUSTOM_OPT_LEVEL})
+target_link_libraries(drivers_accelerometer PRIVATE conversion drivers__device)

src/lib/drivers/gyroscope/CMakeLists.txt

@@ -35,4 +35,5 @@ px4_add_library(drivers_gyroscope
 	PX4Gyroscope.cpp
 	PX4Gyroscope.hpp
 )
+target_compile_options(drivers_gyroscope PRIVATE ${MAX_CUSTOM_OPT_LEVEL})
 target_link_libraries(drivers_gyroscope PRIVATE conversion drivers__device)

src/lib/perf/CMakeLists.txt

@@ -32,4 +32,5 @@
 ############################################################################
 
 add_library(perf perf_counter.cpp)
-add_dependencies(perf prebuild_targets)
+add_dependencies(perf prebuild_targets)
+target_compile_options(perf PRIVATE ${MAX_CUSTOM_OPT_LEVEL})

src/lib/systemlib/CMakeLists.txt

@@ -33,13 +33,17 @@
 
 set(SRCS
 	conversions.c
+	conversions.h
 	crc.c
+	crc.h
 	mavlink_log.cpp
+	mavlink_log.h
 )
 
 if(${PX4_PLATFORM} STREQUAL "nuttx")
 	list(APPEND SRCS
 		cpuload.c
+		cpuload.h
 		print_load_nuttx.c
 		otp.c
 	)
@@ -50,3 +54,4 @@ else()
 endif()
 
 px4_add_library(systemlib ${SRCS})
+target_compile_options(systemlib PRIVATE ${MAX_CUSTOM_OPT_LEVEL})