Add exported libsudo_util functions to util.exp and mark in headers

using __dso_public.

plugins/sudoers/sudoers.c

@@ -70,14 +70,15 @@
 # include <selinux/selinux.h>
 #endif
 #include <ctype.h>
-#ifndef HAVE_GETADDRINFO
-# include "compat/getaddrinfo.h"
-#endif
 
 #include "sudoers.h"
 #include "auth/sudo_auth.h"
 #include "secure_path.h"
 
+#ifndef HAVE_GETADDRINFO
+# include "compat/getaddrinfo.h"
+#endif
+
 /*
  * Prototypes
  */