improved fix

pocketfft_hdronly.h

@@ -110,8 +110,9 @@ constexpr bool FORWARD  = true,
 #if defined(__INTEL_COMPILER)
 // do nothing. This is necessary because this compiler also sets __GNUC__.
 #elif defined(__clang__)
-#ifdef __APPLE__
-#  if (__clang_major__ > 9) || (__clang_major__ == 9 && __clang_minor__ >= 3)
+// AppleClang has their own version numbering
+#ifdef __apple_build_version__
+#  if (__clang_major__ > 9) || (__clang_major__ == 9 && __clang_minor__ >= 1)
 #     undef POCKETFFT_NO_VECTORS
 #  endif
 #elif __clang_major__ >= 5