add S_ macor to mark message for both translation and inclusion into docbook SGML

git-svn-id: https://nagiosplug.svn.sourceforge.net/svnroot/nagiosplug/nagiosplug/trunk@606 f882894a-f735-0410-b71e-b25c423dba1c

plugins/common.h

@@ -159,10 +159,12 @@ enum {
 #if ENABLE_NLS
 #  include "gettext.h"
 #  define _(String) gettext (String)
+#  define S_(String) gettext (String)
 #  define gettext_noop(String) String
 #  define N_(String) gettext_noop String
 #else
 #  define _(String) (String)
+#  define S_(String) (String)
 #  define N_(String) String
 #  define textdomain(Domain)
 #  define bindtextdomain(Package, Directory)