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>

configure.ac

@@ -54,6 +54,11 @@ AC_ARG_ENABLE(sigv1,
 	AM_CONDITIONAL([CONFIG_SIGV1], [test "x$enable_sigv1" = "xyes"])
 	AS_IF([test "$enable_sigv1"  != "yes"], [enable_sigv1="no"])
 
+AC_ARG_ENABLE(engine,
+	      [AS_HELP_STRING([--disable-engine], [build ima-evm-utils without OpenSSL engine support])],,[enable_engine=yes])
+	AC_CHECK_LIB([crypto], [ENGINE_init],, [enable_engine=no])
+	AM_CONDITIONAL([CONFIG_IMA_EVM_ENGINE], [test "x$enable_engine" = "xyes"])
+
 #debug support - yes for a while
 PKG_ARG_ENABLE(debug, "yes", DEBUG, [Enable Debug support])
 if test $pkg_cv_enable_debug = yes; then
@@ -89,5 +94,6 @@ echo	"      tss2-esys: $ac_cv_lib_tss2_esys_Esys_Free"
 echo	" tss2-rc-decode: $ac_cv_lib_tss2_rc_Tss2_RC_Decode"
 echo    "         ibmtss: $ac_cv_header_ibmtss_tss_h"
 echo    "         sigv1:  $enable_sigv1"
+echo    "         engine: $enable_engine"
 echo	"            doc: $have_doc"
 echo