core: fix compile error in COMPAT mode

Signed-off-by: Menglong Dong <imagedong@tencent.com>

Author: menglongdong

shared/bpf/skb_macro.h

@@ -46,8 +46,7 @@
 #endif
 
 #ifdef COMPAT_MODE
-#define bpf_core_helper_exist(name)				\
-	bpf_core_enum_value_exists(enum bpf_func_id, BPF_FUNC_##name)
+#define bpf_core_helper_exist(name) false
 
 #undef bpf_core_type_exists
 #define bpf_core_type_exists(type) false
@@ -61,7 +60,8 @@
 #undef bpf_core_field_offset
 #define bpf_core_field_offset(type, field) offsetof(type, field)
 #else
-#define bpf_core_helper_exist(name) false
+#define bpf_core_helper_exist(name)				\
+	bpf_core_enum_value_exists(enum bpf_func_id, BPF_FUNC_##name)
 #endif
 
 #endif

shared/bpf/skb_parse.h

@@ -7,11 +7,9 @@
 #ifndef _H_BPF_SKB_UTILS
 #define _H_BPF_SKB_UTILS
 
-#undef bpf_core_type_exists
-#undef bpf_core_field_exists
-#undef bpf_core_enum_value_exists
-#undef bpf_core_field_offset
+#ifndef COMPAT_MODE
 #include <bpf/bpf_core_read.h>
+#endif
 
 #include "skb_macro.h"
 #include "skb_shared.h"