build: cleanup audiotoolbox handling

*_at codecs only need the AudioToolbox framework, which is now checked
like the other Apple frameworks.

configure

@@ -2612,10 +2612,6 @@ zlib_encoder_select="zlib"
 zmbv_decoder_select="zlib"
 zmbv_encoder_select="zlib"
 
-# platform codecs
-audiotoolbox_deps="AudioToolbox_AudioToolbox_h"
-audiotoolbox_extralibs="-framework CoreFoundation -framework AudioToolbox -framework CoreMedia"
-
 # hardware accelerators
 crystalhd_deps="libcrystalhd_libcrystalhd_if_h"
 cuda_deps_any="dlopen LoadLibrary"
@@ -5721,7 +5717,6 @@ check_func_headers glob.h glob
 enabled xlib &&
     check_func_headers "X11/Xlib.h X11/extensions/Xvlib.h" XvGetPortAttribute -lXv -lX11 -lXext
 
-check_header AudioToolbox/AudioToolbox.h
 check_header d3d11.h
 check_header direct.h
 check_header dirent.h
@@ -5764,6 +5759,7 @@ check_lib psapi    "windows.h psapi.h"    GetProcessMemoryInfo -lpsapi
 
 check_lib coreservices "CoreServices/CoreServices.h" UTGetOSTypeFromString "-framework CoreServices"
 
+enabled audiotoolbox && check_apple_framework AudioToolbox
 enabled avfoundation && check_apple_framework AVFoundation
 enabled coreimage    && check_apple_framework CoreImage