camlp5: propagate findlib deps pcre2 and fmt

camlp5's META requires pcre2 and fmt, but they were only buildInputs, so
findlib consumers of camlp5 could not resolve them. Move them to
propagatedBuildInputs.

pkgs/development/tools/ocaml/camlp5/default.nix

@@ -8,6 +8,7 @@
   makeWrapper,
   rresult,
   bos,
+  fmt,
   pcre2,
   re,
   camlp-streams,
@@ -52,12 +53,15 @@ stdenv.mkDerivation (
 
     buildInputs = lib.optionals recent [
       bos
-      pcre2
       re
       rresult
     ];
 
-    propagatedBuildInputs = lib.optional recent camlp-streams;
+    propagatedBuildInputs = lib.optionals recent [
+      camlp-streams
+      pcre2
+      fmt
+    ];
 
     strictDeps = true;