--- guestfs-tools-1.47.2/m4/guestfs-ocaml.m4.orig

+++ guestfs-tools-1.47.2/m4/guestfs-ocaml.m4

@@ -166,7 +166,7 @@ EOF

 ])

 dnl Flags we want to pass to every OCaml compiler call.

-OCAML_WARN_ERROR="-warn-error CDEFLMPSUVYZX+52-3"

+OCAML_WARN_ERROR="-warn-error +C+D+E+F+L+M+P+S+U+V+Y+Z+X+52-3-6"

 AC_SUBST([OCAML_WARN_ERROR])

 OCAML_FLAGS="-g -annot $safe_string_option"

 AC_SUBST([OCAML_FLAGS])