Makefile: Improve Hex cache export

We hit the case where the exported Hex cache could not be read again
using `file:consult/2` when we try to restore the ETS table. The problem
was some string generated with `io_lib:format("~p")` which had invalid
Unicode characters according to `file:consult/1`.

The error returned by `file:consult/1` was:

    {51,file_io_server,invalid_unicode}

We are now using `~w` instead of `~p` so string detection is skipped by
io_lib. The result is readable by `file:consult/1`, though the text file
is barely readable by a human now.

1 files changed, 1 insertions, 1 deletions

diff --git a/Makefile b/Makefile
index bb641c5083..a306798e85 100644
--- a/Makefile
+++ b/Makefile
@@ -265,7 +265,7 @@ define dump_hex_cache_to_erl_term
     Key =:= write_concurrency orelse
     Key =:= compressed],
   Entries = ets:tab2list(Tab),
-  ok = file:write_file(Out, io_lib:format("~p.~n~p.~n", [Props, Entries])),
+  ok = file:write_file(Out, io_lib:format("~w.~n~w.~n", [Props, Entries])),
   ok = file:delete(In),
   init:stop().
 endef