jemalloc: fix building emulated x86_64-darwin on aarch64-darwin

pkgs/development/libraries/jemalloc/default.nix

@@ -33,6 +33,9 @@ stdenv.mkDerivation rec {
     # AArch64 has configurable page size up to 64k. The default configuration
     # for jemalloc only supports 4k page sizes.
     ++ lib.optional stdenv.isAarch64 "--with-lg-page=16"
+    # See https://github.com/jemalloc/jemalloc/issues/1997
+    # Using a value of 48 should work on both emulated and native x86_64-darwin.
+    ++ lib.optional (stdenv.isDarwin && stdenv.isx86_64) "--with-lg-vaddr=48"
   ;
 
   NIX_CFLAGS_COMPILE = lib.optionalString stdenv.isDarwin "-Wno-error=array-bounds";