Fixing sigsegv on Mach x86_64 - possibly a hack; I'm not sure why the

address returned doesn't have that bit set already.

BasiliskII/src/Unix/configure.ac

@@ -472,10 +472,8 @@ AC_CHECK_FILE([/dev/ptc],
 		have_dev_ptc=1
 	]
 )
-
 dnl (end of code from openssh-3.2.2p1 configure.ac)
 
-
 dnl Check for systems where POSIX-style non-blocking I/O (O_NONBLOCK)
 dnl doesn't work or is unimplemented. On these systems (mostly older
 dnl ones), use the old BSD-style FIONBIO approach instead. [tcl.m4]
@@ -982,6 +980,9 @@ AC_CACHE_CHECK([whether your system supports Mach exceptions],
   AC_LANG_SAVE
   AC_LANG_CPLUSPLUS
   AC_TRY_RUN([
+    #define HAVE_UNISTD_H 1
+    #define HAVE_MACH_VM 1
+    #define HAVE_MACH_TASK_SELF 1
     #define HAVE_MACH_EXCEPTIONS 1
     #define CONFIGURE_TEST_SIGSEGV_RECOVERY
     #include "vm_alloc.cpp"

BasiliskII/src/Unix/sigsegv.h

@@ -89,6 +89,7 @@ extern "C" {
 #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.MACH_FIELD_NAME(eax)) /* EAX is the first GPR we consider */
+#define SIGSEGV_FAULT_ADDRESS_FAST		code[1]
 #endif
 #ifdef __x86_64__
 #if __DARWIN_UNIX03 && defined _STRUCT_X86_THREAD_STATE64
@@ -104,8 +105,8 @@ extern "C" {
 #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.MACH_FIELD_NAME(rax)) /* RAX is the first GPR we consider */
+#define SIGSEGV_FAULT_ADDRESS_FAST		(((uint64_t)code[1])|0x100000000)
 #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, mach_exception_data_t code
 #define SIGSEGV_FAULT_HANDLER_ARGS		thread, code