diff --git a/third_party/pocketfft/pocketfft_hdronly.h b/third_party/pocketfft/pocketfft_hdronly.h
--- a/third_party/pocketfft/pocketfft_hdronly.h
+++ b/third_party/pocketfft/pocketfft_hdronly.h
@@ -149,7 +149,7 @@ template<> struct VLEN<double> { static constexpr size_t val=2; };
 #endif
 #endif
 
-#if __cplusplus >= 201703L
+#if defined(__linux__) && __cplusplus >= 201703L
 inline void *aligned_alloc(size_t align, size_t size)
   {
   // aligned_alloc() requires that the requested size is a multiple of "align"