Remove pointer auth flags

See: https://github.com/wolfcw/libfaketime/issues/506
From: https://github.com/wolfcw/libfaketime/pull/509

diff -urN a/src/Makefile.OSX b/src/Makefile.OSX
--- a/src/Makefile.OSX	2025-06-09 12:31:15.000000000 +0000
+++ b/src/Makefile.OSX	2025-11-26 03:22:52.395777231 +0000
@@ -72,8 +72,7 @@
 ARCH := $(shell uname -m)
 
 ifeq ($(ARCH),arm64)
-    CFLAGS += -arch arm64e -arch arm64
-    CFLAGS += -fptrauth-calls -fptrauth-returns
+    CFLAGS += -arch arm64
 endif
 
 SONAME = 1
