diff --git a/BasiliskII/src/uae_cpu/spcflags.h b/BasiliskII/src/uae_cpu/spcflags.h
index a4082a2a..815886ea 100644
--- a/BasiliskII/src/uae_cpu/spcflags.h
+++ b/BasiliskII/src/uae_cpu/spcflags.h
@@ -57,7 +57,7 @@ enum {
 	regs.spcflags &= ~(m); \
 } while (0)
 
-#elif defined(__i386__) && defined(X86_ASSEMBLY)
+#elif (defined(__i386__) || defined(__x86_64__)) && defined(X86_ASSEMBLY)
 
 #define HAVE_HARDWARE_LOCKS