extern "C" {
#endif
+#include <features.h>
+
#include <signal.h>
-#ifdef _GNU_SOURCE
-#define ucontext __ucontext
+#if defined(_GNU_SOURCE) || defined(_BSD_SOURCE)
+#define NGREG (sizeof(gregset_t)/sizeof(greg_t))
#endif
-int getcontext(ucontext_t *);
-void makecontext(ucontext_t *, void (*)(void), int, ...);
-int setcontext(const ucontext_t *);
-int swapcontext(ucontext_t *, const ucontext_t *);
+struct __ucontext;
+
+int getcontext(struct __ucontext *);
+void makecontext(struct __ucontext *, void (*)(), int, ...);
+int setcontext(const struct __ucontext *);
+int swapcontext(struct __ucontext *, const struct __ucontext *);
#ifdef __cplusplus
}