LegacyControllerMappingFileHandler: Add missing cond-compile for building without HID

[fwcd]

This is something I stumbled upon while building Mixxx without HID support. Everything in controllers/hid is only available when -DHID=ON, including legacyhidcontrollermappingfilehandler.h:

mixxx/CMakeLists.txt

Lines 3354 to 3408 in 59ca3a2

	option(HID "USB HID controller support" ON)
	if(HID)
	# hidapi 0.11.2 is the first release, that implements hid_get_input_report
	# for the Linux hidraw backend.
	find_package(hidapi 0.11.2)
	if(NOT hidapi_FOUND)
	message(STATUS "Linking internal libhidapi statically")
	add_library(mixxx-hidapi STATIC EXCLUDE_FROM_ALL)
	target_include_directories(mixxx-hidapi SYSTEM PUBLIC lib/hidapi/hidapi)
	if(WIN32)
	target_sources(mixxx-hidapi PRIVATE lib/hidapi/windows/hid.c)
	find_library(Setupapi_LIBRARY Setupapi REQUIRED)
	target_link_libraries(mixxx-hidapi PUBLIC ${Setupapi_LIBRARY})
	elseif(APPLE)
	target_sources(mixxx-hidapi PRIVATE lib/hidapi/mac/hid.c)
	find_library(AppKit_LIBRARY AppKit REQUIRED)
	target_link_libraries(mixxx-hidapi PUBLIC ${AppKit_LIBRARY})
	elseif(UNIX)
	if(CMAKE_SYSTEM_NAME STREQUAL Linux)
	find_library(libudev_LIBRARY udev REQUIRED)
	target_sources(mixxx-hidapi PRIVATE lib/hidapi/linux/hid.c)
	target_link_libraries(mixxx-hidapi PRIVATE ${libudev_LIBRARY})
	else()
	if(NOT LibUSB_FOUND)
	message(FATAL_ERROR "USB HID controller support on Unix with statically linked libhidapi-libusb requires libusb 1.0 and its development headers.")
	endif()
	target_sources(mixxx-hidapi PRIVATE lib/hidapi/libusb/hid.c)
	target_link_libraries(mixxx-hidapi PRIVATE LibUSB::LibUSB)
	endif()
	else()
	message(FATAL_ERROR "USB HID controller support only possible on Windows/Mac OS/Linux/BSD.")
	endif()
	target_link_libraries(mixxx-lib PRIVATE mixxx-hidapi)
	else()
	# hidapi has two backends on Linux, one using the kernel's hidraw API and one using libusb.
	# libusb obviously does not support Bluetooth HID devices, so use the hidraw backend. The
	# libusb backend is the default, so hidraw needs to be selected explicitly at link time.
	if(CMAKE_SYSTEM_NAME STREQUAL Linux)
	target_link_libraries(mixxx-lib PRIVATE hidapi::hidraw)
	else()
	target_link_libraries(mixxx-lib PRIVATE hidapi::hidapi)
	endif()
	endif()
	target_sources(mixxx-lib PRIVATE
	src/controllers/hid/hidcontroller.cpp
	src/controllers/hid/hidiothread.cpp
	src/controllers/hid/hidioglobaloutputreportfifo.cpp
	src/controllers/hid/hidiooutputreport.cpp
	src/controllers/hid/hiddevice.cpp
	src/controllers/hid/hidenumerator.cpp
	src/controllers/hid/legacyhidcontrollermapping.cpp
	src/controllers/hid/legacyhidcontrollermappingfilehandler.cpp
	)
	target_compile_definitions(mixxx-lib PUBLIC __HID__)
	endif()

LegacyControllerMappingFileHandler was missing a cond-compile around the HID handler, therefore this patch.

[JoergAtGithub]

LGTM! Thank you!