-void(*p_siglongjmp)(sigjmp_buf,int) = siglongjmp;
-int(*p_sigsetjmp)(sigjmp_buf,int) = sigsetjmp;
+{void(*p)(sigjmp_buf,int) = siglongjmp;}
+#ifdef sigsetjmp
+{int x = sigsetjmp((sigjmp_buf){0}, 0);}
+#else
+{int(*p)(sigjmp_buf,int) = sigsetjmp;}
+#endif
+#endif
+#if defined _XOPEN_SOURCE && defined OBSOLETE
+{void(*p)(jmp_buf,int) = _longjmp;}
+#ifdef _setjmp
+{int x = _setjmp((jmp_buf){0});}
+#else
+{int(*p)(jmp_buf) = _setjmp;}
+#endif