mach: undef ENTRY2

This macro from Mach headers conflicts with how
sysdeps/x86_64/multiarch/strcmp-sse2.S expects it to be defined.

Signed-off-by: Sergey Bugaev <bugaevc@gmail.com>
Message-Id: <20230214173722.428140-3-bugaevc@gmail.com>

sysdeps/mach/sysdep.h

@@ -30,6 +30,7 @@
 /* For ELF we need to add the `.type' directive to make shared libraries
    work right.  */
 #undef ENTRY
+#undef ENTRY2
 #define ENTRY(name) \
   .globl name; \
   .align ALIGN; \