doc: document deprecated engine configure options

Document that no-engine, no-static-engine, and no-dynamic-engine
configure options are deprecated and do nothing. These options are
retained for backwards compatibility only.

Fixes #27473

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
Reviewed-by: Eugene Syromiatnikov <esyr@openssl.org>
Reviewed-by: Nikola Pajkovsky <nikolap@openssl.org>
Reviewed-by: Milan Broz <mbroz@openssl.org>
MergeDate: Thu Jun 11 09:02:08 2026
(Merged from https://github.com/openssl/openssl/pull/29839)

diff --git a/INSTALL.md b/INSTALL.md
index f6d4a132de71ddc552936ee7ee3e3873f6aca171..ae31b8207c0551f5ca6deb5144f3a11d4a2daca8 100644 (file)
--- a/INSTALL.md
+++ b/INSTALL.md
@@ -868,6 +868,13 @@ Note that if this feature is enabled then GOST ciphersuites are only available
 if the GOST algorithms are also available through loading an externally supplied
 engine.
 
+### no-engine, no-static-engine, no-dynamic-engine
+
+The `no-engine` option is always present.  These options are deprecated and do
+nothing, and are retained for backwards compatibility only.  The ENGINE API was
+deprecated in OpenSSL 3.0 and removed in OpenSSL 4.0, so applications should
+transition to using providers instead.
+
 ### no-http
 
 Disable HTTP support.