cmake enable -Wcast-align and disable per module

cmake/px4_add_common_flags.cmake

@@ -66,6 +66,7 @@ function(px4_add_common_flags)
 		-Werror
 
 		-Warray-bounds
+		-Wcast-align
 		-Wdisabled-optimization
 		-Wdouble-promotion
 		-Wfatal-errors
@@ -79,8 +80,6 @@ function(px4_add_common_flags)
 		-Wunknown-pragmas
 		-Wunused-variable
 
-		#-Wcast-align # TODO: fix and enable
-
 		# disabled warnings
 		-Wno-implicit-fallthrough # set appropriate level and update
 		-Wno-missing-field-initializers

cmake/px4_add_module.cmake

@@ -118,6 +118,10 @@ function(px4_add_module)
 		add_library(${MODULE} STATIC EXCLUDE_FROM_ALL ${CMAKE_CURRENT_BINARY_DIR}/${MODULE}_unity.cpp)
 		target_include_directories(${MODULE} PRIVATE ${CMAKE_CURRENT_SOURCE_DIR})
 
+		if(COMPILE_FLAGS)
+			target_compile_options(${MODULE}_original PRIVATE ${COMPILE_FLAGS})
+		endif()
+
 		if(DEPENDS)
 			# using target_link_libraries for dependencies provides linking
 			#  as well as interface include and libraries