diff --git a/BasiliskII/src/Unix/sigsegv.cpp b/BasiliskII/src/Unix/sigsegv.cpp
index 4fc49a9d..68f5ee3c 100644
--- a/BasiliskII/src/Unix/sigsegv.cpp
+++ b/BasiliskII/src/Unix/sigsegv.cpp
@@ -627,58 +627,74 @@ if (ret != KERN_SUCCESS) { \
 }
 
 #ifdef __ppc__
+#if __DARWIN_UNIX03 && defined _STRUCT_PPC_THREAD_STATE
+#define MACH_FIELD_NAME(X)				__CONCAT(__,X)
+#endif
 #define SIGSEGV_EXCEPTION_STATE_TYPE	ppc_exception_state_t
 #define SIGSEGV_EXCEPTION_STATE_FLAVOR	PPC_EXCEPTION_STATE
 #define SIGSEGV_EXCEPTION_STATE_COUNT	PPC_EXCEPTION_STATE_COUNT
-#define SIGSEGV_FAULT_ADDRESS			SIP->exc_state.dar
+#define SIGSEGV_FAULT_ADDRESS			SIP->exc_state.MACH_FIELD_NAME(dar)
 #define SIGSEGV_THREAD_STATE_TYPE		ppc_thread_state_t
 #define SIGSEGV_THREAD_STATE_FLAVOR		PPC_THREAD_STATE
 #define SIGSEGV_THREAD_STATE_COUNT		PPC_THREAD_STATE_COUNT
-#define SIGSEGV_FAULT_INSTRUCTION		SIP->thr_state.srr0
+#define SIGSEGV_FAULT_INSTRUCTION		SIP->thr_state.MACH_FIELD_NAME(srr0)
 #define SIGSEGV_SKIP_INSTRUCTION		powerpc_skip_instruction
-#define SIGSEGV_REGISTER_FILE			(unsigned long *)&SIP->thr_state.srr0, (unsigned long *)&SIP->thr_state.r0
+#define SIGSEGV_REGISTER_FILE			(unsigned long *)&SIP->thr_state.MACH_FIELD_NAME(srr0), (unsigned long *)&SIP->thr_state.MACH_FIELD_NAME(r0)
 #endif
 #ifdef __ppc64__
+#if __DARWIN_UNIX03 && defined _STRUCT_PPC_THREAD_STATE64
+#define MACH_FIELD_NAME(X)				__CONCAT(__,X)
+#endif
 #define SIGSEGV_EXCEPTION_STATE_TYPE	ppc_exception_state64_t
 #define SIGSEGV_EXCEPTION_STATE_FLAVOR	PPC_EXCEPTION_STATE64
 #define SIGSEGV_EXCEPTION_STATE_COUNT	PPC_EXCEPTION_STATE64_COUNT
-#define SIGSEGV_FAULT_ADDRESS			SIP->exc_state.dar
+#define SIGSEGV_FAULT_ADDRESS			SIP->exc_state.MACH_FIELD_NAME(dar)
 #define SIGSEGV_THREAD_STATE_TYPE		ppc_thread_state64_t
 #define SIGSEGV_THREAD_STATE_FLAVOR		PPC_THREAD_STATE64
 #define SIGSEGV_THREAD_STATE_COUNT		PPC_THREAD_STATE64_COUNT
-#define SIGSEGV_FAULT_INSTRUCTION		SIP->thr_state.srr0
+#define SIGSEGV_FAULT_INSTRUCTION		SIP->thr_state.MACH_FIELD_NAME(srr0)
 #define SIGSEGV_SKIP_INSTRUCTION		powerpc_skip_instruction
-#define SIGSEGV_REGISTER_FILE			(unsigned long *)&SIP->thr_state.srr0, (unsigned long *)&SIP->thr_state.r0
+#define SIGSEGV_REGISTER_FILE			(unsigned long *)&SIP->thr_state.MACH_FIELD_NAME(srr0), (unsigned long *)&SIP->thr_state.MACH_FIELD_NAME(r0)
 #endif
 #ifdef __i386__
-#define SIGSEGV_EXCEPTION_STATE_TYPE	struct i386_exception_state
+#if __DARWIN_UNIX03 && defined _STRUCT_X86_THREAD_STATE32
+#define MACH_FIELD_NAME(X)				__CONCAT(__,X)
+#endif
+#define SIGSEGV_EXCEPTION_STATE_TYPE	i386_exception_state_t
 #define SIGSEGV_EXCEPTION_STATE_FLAVOR	i386_EXCEPTION_STATE
 #define SIGSEGV_EXCEPTION_STATE_COUNT	i386_EXCEPTION_STATE_COUNT
-#define SIGSEGV_FAULT_ADDRESS			SIP->exc_state.faultvaddr
-#define SIGSEGV_THREAD_STATE_TYPE		struct i386_thread_state
+#define SIGSEGV_FAULT_ADDRESS			SIP->exc_state.MACH_FIELD_NAME(faultvaddr)
+#define SIGSEGV_THREAD_STATE_TYPE		i386_thread_state_t
 #define SIGSEGV_THREAD_STATE_FLAVOR		i386_THREAD_STATE
 #define SIGSEGV_THREAD_STATE_COUNT		i386_THREAD_STATE_COUNT
-#define SIGSEGV_FAULT_INSTRUCTION		SIP->thr_state.eip
+#define SIGSEGV_FAULT_INSTRUCTION		SIP->thr_state.MACH_FIELD_NAME(eip)
 #define SIGSEGV_SKIP_INSTRUCTION		ix86_skip_instruction
-#define SIGSEGV_REGISTER_FILE			((SIGSEGV_REGISTER_TYPE *)&SIP->thr_state.eax) /* EAX is the first GPR we consider */
+#define SIGSEGV_REGISTER_FILE			((SIGSEGV_REGISTER_TYPE *)&SIP->thr_state.MACH_FIELD_NAME(eax)) /* EAX is the first GPR we consider */
 #endif
 #ifdef __x86_64__
-#define SIGSEGV_EXCEPTION_STATE_TYPE	struct x86_exception_state64
+#if __DARWIN_UNIX03 && defined _STRUCT_X86_THREAD_STATE64
+#define MACH_FIELD_NAME(X)				__CONCAT(__,X)
+#endif
+#define SIGSEGV_EXCEPTION_STATE_TYPE	x86_exception_state64_t
 #define SIGSEGV_EXCEPTION_STATE_FLAVOR	x86_EXCEPTION_STATE64
 #define SIGSEGV_EXCEPTION_STATE_COUNT	x86_EXCEPTION_STATE64_COUNT
-#define SIGSEGV_FAULT_ADDRESS			SIP->exc_state.faultvaddr
-#define SIGSEGV_THREAD_STATE_TYPE		struct x86_thread_state64
+#define SIGSEGV_FAULT_ADDRESS			SIP->exc_state.MACH_FIELD_NAME(faultvaddr)
+#define SIGSEGV_THREAD_STATE_TYPE		x86_thread_state64_t
 #define SIGSEGV_THREAD_STATE_FLAVOR		x86_THREAD_STATE64
 #define SIGSEGV_THREAD_STATE_COUNT		x86_THREAD_STATE64_COUNT
-#define SIGSEGV_FAULT_INSTRUCTION		SIP->thr_state.rip
+#define SIGSEGV_FAULT_INSTRUCTION		SIP->thr_state.MACH_FIELD_NAME(rip)
 #define SIGSEGV_SKIP_INSTRUCTION		ix86_skip_instruction
-#define SIGSEGV_REGISTER_FILE			((SIGSEGV_REGISTER_TYPE *)&SIP->thr_state.rax) /* RAX is the first GPR we consider */
+#define SIGSEGV_REGISTER_FILE			((SIGSEGV_REGISTER_TYPE *)&SIP->thr_state.MACH_FIELD_NAME(rax)) /* RAX is the first GPR we consider */
 #endif
 #define SIGSEGV_FAULT_ADDRESS_FAST		code[1]
 #define SIGSEGV_FAULT_INSTRUCTION_FAST	SIGSEGV_INVALID_ADDRESS
 #define SIGSEGV_FAULT_HANDLER_ARGLIST	mach_port_t thread, exception_data_t code
 #define SIGSEGV_FAULT_HANDLER_ARGS		thread, code
 
+#ifndef MACH_FIELD_NAME
+#define MACH_FIELD_NAME(X) X
+#endif
+
 // Since there can only be one exception thread running at any time
 // this is not a problem.
 #define MSG_SIZE 512