Move a type to where it's used

alc/alu.cpp

@@ -151,6 +151,10 @@ struct ChanMap {
     float elevation;
 };
 
+using HrtfDirectMixerFunc = void(*)(FloatBufferLine &LeftOut, FloatBufferLine &RightOut,
+    const al::span<const FloatBufferLine> InSamples, float2 *AccumSamples, DirectHrtfState *State,
+    const size_t BufferSize);
+
 HrtfDirectMixerFunc MixDirectHrtf{MixDirectHrtf_<CTag>};
 
 inline HrtfDirectMixerFunc SelectHrtfMixer(void)

alc/alu.h

@@ -21,9 +21,6 @@ struct ALeffectslot;
 using MixerFunc = void(*)(const al::span<const float> InSamples,
     const al::span<FloatBufferLine> OutBuffer, float *CurrentGains, const float *TargetGains,
     const size_t Counter, const size_t OutPos);
-using HrtfDirectMixerFunc = void(*)(FloatBufferLine &LeftOut, FloatBufferLine &RightOut,
-    const al::span<const FloatBufferLine> InSamples, float2 *AccumSamples, DirectHrtfState *State,
-    const size_t BufferSize);
 
 extern MixerFunc MixSamples;