Moved the bad-function-cast compiler warning option out of the common flags and into

the nuttx and posix specific options files since this option cannot be used with
the qurt platform. There are header files in the hexagon sdk that fail this check.

cmake/px4_add_common_flags.cmake

@@ -144,7 +144,6 @@ function(px4_add_common_flags)
 	list(APPEND c_flags
 		-fno-common
 
-		-Wbad-function-cast
 		-Wnested-externs
 		-Wstrict-prototypes
 	)

platforms/nuttx/cmake/px4_impl_os.cmake

@@ -69,6 +69,8 @@ function(px4_os_add_flags)
 
 	add_compile_options($<$<COMPILE_LANGUAGE:CXX>:-fno-sized-deallocation>)
 
+	add_compile_options($<$<COMPILE_LANGUAGE:C>:-Wbad-function-cast>)
+
 	add_definitions(
 		-D__PX4_NUTTX
 

platforms/posix/cmake/px4_impl_os.cmake

@@ -238,6 +238,8 @@ function(px4_os_add_flags)
 
 	endif()
 
+	add_compile_options($<$<COMPILE_LANGUAGE:C>:-Wbad-function-cast>)
+
 endfunction()
 
 #=============================================================================