kconfig: allow build-time definition of the internal config prefix

Signed-off-by: Arnaud Lacombe <lacombar@gmail.com>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Reviewed-by: Michal Marek <mmarek@suse.cz>
diff --git a/scripts/kconfig/mconf.c b/scripts/kconfig/mconf.c
index 5c3d0c4..17ba222 100644
--- a/scripts/kconfig/mconf.c
+++ b/scripts/kconfig/mconf.c
@@ -316,8 +316,8 @@
 again:
 	dialog_clear();
 	dres = dialog_inputbox(_("Search Configuration Parameter"),
-			      _("Enter CONFIG_ (sub)string to search for "
-				"(with or without \"CONFIG\")"),
+			      _("Enter " CONFIG_ " (sub)string to search for "
+				"(with or without \"" CONFIG_ "\")"),
 			      10, 75, "");
 	switch (dres) {
 	case 0:
@@ -329,10 +329,10 @@
 		return;
 	}
 
-	/* strip CONFIG_ if necessary */
+	/* strip the prefix if necessary */
 	dialog_input = dialog_input_result;
-	if (strncasecmp(dialog_input_result, "CONFIG_", 7) == 0)
-		dialog_input += 7;
+	if (strncasecmp(dialog_input_result, CONFIG_, strlen(CONFIG_)) == 0)
+		dialog_input += strlen(CONFIG_);
 
 	sym_arr = sym_re_search(dialog_input);
 	res = get_relations_str(sym_arr);