configure: Fix (deprecated) plugin option

Actually two issues here.

On one hand there was the incomplete rename from --enable-plugin to
--enable-plugin-deprecated triggering new warnings with
dropbear-2026.92.  Technically new options where ignored while the old
--enable-plugin and --disable-plugin where still considered.

On the other hand the previous option was broken from the beginning,
because when passing --enable-plugin or --disable-plugin explicitly the
option was not evaluated correctly.

Link: https://www.gnu.org/software/autoconf/manual/autoconf-2.71/html_node/Package-Options.html
Fixes: 8c6aaf8 ("External Public-Key Authentication API (#72)")
Fixes: #298
Fixes: e3e7b28 ("Make -t two factor and plugins deprecated")
Signed-off-by: Alexander Dahl <ada@thorsis.com>

Author: LeSpocky

configure

@@ -736,7 +736,7 @@ enable_pam
 enable_openpty
 enable_syslog
 enable_shadow
-enable_plugin
+enable_plugin_deprecated
 enable_fuzz
 enable_bundled_libtom
 enable_lastlog
@@ -5838,22 +5838,33 @@ fi
 
 
 # Plugin support will be removed soon. Open a github issue if you're using it.
-# Check whether --enable-plugin was given.
-if test ${enable_plugin+y}
+# Check whether --enable-plugin-deprecated was given.
+if test ${enable_plugin_deprecated+y}
 then :
-  enableval=$enable_plugin;
+  enableval=$enable_plugin_deprecated;
+		if test "x$enableval" = "xyes"; then
 
 printf "%s\n" "#define DROPBEAR_PLUGIN 1" >>confdefs.h
 
-		{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: Enabling support for External Public Key Authentication" >&5
+			{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: Enabling support for External Public Key Authentication" >&5
 printf "%s\n" "$as_me: Enabling support for External Public Key Authentication" >&6;}
-		DROPBEAR_PLUGIN=1
+			DROPBEAR_PLUGIN=1
+		else
+
+printf "%s\n" "#define DROPBEAR_PLUGIN 0" >>confdefs.h
+
+			{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: Disabling support for External Public Key Authentication" >&5
+printf "%s\n" "$as_me: Disabling support for External Public Key Authentication" >&6;}
+			DROPBEAR_PLUGIN=0
+		fi
 
 else $as_nop
 
 
 printf "%s\n" "#define DROPBEAR_PLUGIN 0" >>confdefs.h
 
+		{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: Disabling support for External Public Key Authentication" >&5
+printf "%s\n" "$as_me: Disabling support for External Public Key Authentication" >&6;}
 		DROPBEAR_PLUGIN=0
 
 

configure.ac

@@ -345,15 +345,22 @@ AC_ARG_ENABLE(shadow,
 )
 
 # Plugin support will be removed soon. Open a github issue if you're using it.
-AC_ARG_ENABLE(plugin,
+AC_ARG_ENABLE(plugin-deprecated,
 	[AS_HELP_STRING([--enable-plugin-deprecated], [Enable support for External Public Key Authentication plug-in])],
 	[
-		AC_DEFINE(DROPBEAR_PLUGIN, 1, External Public Key Authentication)
-		AC_MSG_NOTICE(Enabling support for External Public Key Authentication)
-		DROPBEAR_PLUGIN=1
+		if test "x$enableval" = "xyes"; then
+			AC_DEFINE(DROPBEAR_PLUGIN, 1, External Public Key Authentication)
+			AC_MSG_NOTICE(Enabling support for External Public Key Authentication)
+			DROPBEAR_PLUGIN=1
+		else
+			AC_DEFINE(DROPBEAR_PLUGIN, 0, External Public Key Authentication)
+			AC_MSG_NOTICE(Disabling support for External Public Key Authentication)
+			DROPBEAR_PLUGIN=0
+		fi
 	],
 	[
 		AC_DEFINE(DROPBEAR_PLUGIN, 0, External Public Key Authentication)
+		AC_MSG_NOTICE(Disabling support for External Public Key Authentication)
 		DROPBEAR_PLUGIN=0
 	]