diff --git a/BasiliskII/src/MacOSX/clip_macosx64.cpp b/BasiliskII/src/MacOSX/clip_macosx64.cpp
index 496e457a..769a8a0b 100644
--- a/BasiliskII/src/MacOSX/clip_macosx64.cpp
+++ b/BasiliskII/src/MacOSX/clip_macosx64.cpp
@@ -77,7 +77,7 @@ static int GetMacScriptManagerVariable(uint16 id)
 		0x2f, 0x3c, 0x84, 0x02, 0x00, 0x08, // move.l	 #-2080243704,-(sp)
 		0xa8, 0xb5,							// ScriptUtil()
 		0x20, 0x1f,							// move.l	 (a7)+,d0
-		M68K_RTS >> 8, M68K_RTS
+		M68K_RTS >> 8, M68K_RTS & 0xff
 	};
 	r.d[0] = sizeof(proc);
 	Execute68kTrap(0xa71e, &r);		// NewPtrSysClear()
diff --git a/SheepShaver/src/Unix/configure.ac b/SheepShaver/src/Unix/configure.ac
index b2bf3f63..4b20ee49 100644
--- a/SheepShaver/src/Unix/configure.ac
+++ b/SheepShaver/src/Unix/configure.ac
@@ -708,7 +708,18 @@ if [[ "x$WANT_SDL_VIDEO" = "xyes" ]]; then
   VIDEOSRCS="../SDL/video_sdl.cpp"
   KEYCODES="../SDL/keycodes"
   if [[ "x$ac_cv_framework_Carbon" = "xyes" ]]; then
-    EXTRASYSSRCS="$EXTRASYSSRCS ../MacOSX/clip_macosx.cpp"
+    AC_MSG_CHECKING([whether __LP64__ is defined])
+    AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[#if !defined(__LP64__)
+                                         # error __LP64__ not defined
+                                         #endif
+                                       ]])],
+                      [AC_MSG_RESULT(yes); LP64_DEFINED=yes],
+                      [AC_MSG_RESULT(no)])
+    if [[ "x$LP64_DEFINED" = "xyes" ]]; then
+      EXTRASYSSRCS="$EXTRASYSSRCS ../MacOSX/clip_macosx64.cpp"
+    else
+      EXTRASYSSRCS="$EXTRASYSSRCS ../MacOSX/clip_macosx.cpp"
+    fi
     EXTRASYSSRCS="$EXTRASYSSRCS ../MacOSX/utils_macosx.mm"
     CPPFLAGS="$CPPFLAGS -I../MacOSX"
   else