Add mention of OPENSSL_ENGINE_STUBS to openssl_user_macros(7)

Fixes openssl/project#1743
Fixes openssl/project#1744

Signed-off-by: Milan Broz <gmazyland@gmail.com>
Reviewed-by: Neil Horman <nhorman@openssl.org>
Reviewed-by: Norbert Pocs <norbertp@openssl.org>
Reviewed-by: Eugene Syromiatnikov <esyr@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/29424)

diff --git a/doc/man7/openssl_user_macros.pod.in b/doc/man7/openssl_user_macros.pod.in
index 829fe69aeb40f6a8d417e7655131184d950d7bc9..b579a03af01a373dd50838e65deac1a55c8c45f6 100644 (file)
--- a/doc/man7/openssl_user_macros.pod.in
+++ b/doc/man7/openssl_user_macros.pod.in
@@ -88,6 +88,17 @@ versions up to and including the version given by B<OPENSSL_API_COMPAT>
 (or the default value given above, when B<OPENSSL_API_COMPAT> isn't defined)
 will be hidden.
 
+=item B<OPENSSL_ENGINE_STUBS>
+
+ENGINE API, as defined in openssl/engine.h, was permanently removed in OpenSSL 4.0.
+
+The user application can use the define B<OPENSSL_ENGINE_STUBS> to enable stub macros
+for API ENGINE functions. It should temporarily help the easy transition of applications
+without source code modifications.
+
+Note that all stub macros emulate API function failures; they will not restore
+the removed API even if the B<OPENSSL_API_COMPAT> define is used.
+
 =back
 
 =head1 COPYRIGHT