Fix various warnings reported by clang

- mostly remove unused variables
- rename some generic JIT identifiers

Source/Core/VideoCommon/VertexLoader.h

@@ -17,6 +17,11 @@
 #include "VideoCommon/DataReader.h"
 #include "VideoCommon/NativeVertexFormat.h"
 
+#ifndef _M_GENERIC
+#ifndef __APPLE__
+#define USE_VERTEX_LOADER_JIT
+#endif
+#endif
 
 class VertexLoaderUID
 {
@@ -119,9 +124,11 @@ private:
 	NativeVertexFormat *m_NativeFmt;
 	int native_stride;
 
-	// Pipeline. To be JIT compiled in the future.
+#ifndef USE_VERTEX_LOADER_JIT
+	// Pipeline.
 	TPipelineFunction m_PipelineStages[64];  // TODO - figure out real max. it's lower.
 	int m_numPipelineStages;
+#endif
 
 	const u8 *m_compiledCode;