-#if defined(_XOPEN_SOURCE) || defined(_GNU_SOURCE)
-int _setjmp (jmp_buf);
-void _longjmp (jmp_buf, int);
+#if defined(_POSIX_SOURCE) || defined(_POSIX_C_SOURCE) \
+ || defined(_XOPEN_SOURCE) || defined(_GNU_SOURCE) \
+ || defined(_BSD_SOURCE)
+typedef jmp_buf sigjmp_buf;
+int sigsetjmp (sigjmp_buf, int) __setjmp_attr;
+_Noreturn void siglongjmp (sigjmp_buf, int);