Disable use of OpenSSL "engine" support

OpenSSL v3 "engine" support is deprecated and replaced with "providers".
Engine support will continue to work for a while, but results in
deprecated declaration and other messages.  One option is simply to hide
them ("-Wno-deprecated-declarations").  The other alternative is to
conditionally build ima-evm-utils without OpenSSL engine support and
without disabling deprecated declarations.

Based on "--disable-engine" or "--enable-engine=no" configuration
option, disable OpenSSL "engine" support.

As suggested by Vitaly,
- verify ENGINE_init symbol is defined in libcrypto
- disable engine support if either OPENSSL_NO_DYNAMIC_ENGINE or
OPENSSL_NO_ENGINE variables are defined

Reviewed-by: Stefan Berger <stefanb@linux.ibm.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>

src/imaevm.h

@@ -48,7 +48,13 @@
 #include <errno.h>
 #include <sys/types.h>
 #include <openssl/rsa.h>
+#ifdef CONFIG_IMA_EVM_ENGINE
 #include <openssl/engine.h>
+#endif
+
+#if defined(OPENSSL_NO_ENGINE) || defined(OPENSSL_NO_DYNAMIC_ENGINE)
+#undef CONFIG_IMA_EVM_ENGINE
+#endif
 
 #ifdef USE_FPRINTF
 #define do_log(level, fmt, args...)	\