diff --git /usr/include/mach/arm/_structs.h /usr/include/mach/arm/_structs.h
index e130afa..1f98c98 100644
--- /usr/include/mach/arm/_structs.h
+++ /usr/include/mach/arm/_structs.h
@@ -25,7 +25,7 @@ _STRUCT_ARM_EXCEPTION_STATE
 };
 #endif /* __DARWIN_UNIX03 */

-#if __DARWIN_UNIX03
+#if __DARWIN_UNIX03 || 1
 #define _STRUCT_ARM_THREAD_STATE	struct __darwin_arm_thread_state
 _STRUCT_ARM_THREAD_STATE
 {
diff --git /usr/include/arm/_structs.h /usr/include/arm/_structs.h
index 2834b48..6c14349 100644
--- /usr/include/arm/_structs.h
+++ /usr/include/arm/_structs.h
@@ -38,6 +38,14 @@ _STRUCT_MCONTEXT
 #endif /* _STRUCT_MCONTEXT */
 #endif /* __need_struct_mcontext */
 
+#ifdef __need_mcontext_t
+#undef __need_mcontext_t
+#ifndef _MCONTEXT_T
+#define _MCONTEXT_T
+typedef _STRUCT_MCONTEXT	*mcontext_t;
+#endif /* _MCONTEXT_T */
+#endif /* __need_mcontext_t */
+
 #if !defined(_POSIX_C_SOURCE) || defined(_DARWIN_C_SOURCE)
 #ifndef ARM_MCONTEXT_SIZE
 #define ARM_MCONTEXT_SIZE       (ARM_THREAD_STATE_COUNT + ARM_VFP_STATE_COUNT + ARM_EXCEPTION_STATE_COUNT) * sizeof(int)