bpf_helpers.h: Define bpf_tail_call_static when building with GCC

The definition of bpf_tail_call_static in tools/lib/bpf/bpf_helpers.h
is guarded by a preprocessor check to assure that clang is recent
enough to support it.  This patch updates the guard so the function is
compiled when using GCC 13 or later as well.

Tested in bpf-next master. No regressions.
Signed-off-by: Jose E. Marchesi <jose.marchesi@oracle.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20240426145158.14409-1-jose.marchesi@oracle.com

tools/lib/bpf/bpf_helpers.h

@@ -137,7 +137,8 @@
 /*
  * Helper function to perform a tail call with a constant/immediate map slot.
  */
-#if __clang_major__ >= 8 && defined(__bpf__)
+#if (defined(__clang__) && __clang_major__ >= 8) || (!defined(__clang__) && __GNUC__ > 12)
+#if defined(__bpf__)
 static __always_inline void
 bpf_tail_call_static(void *ctx, const void *map, const __u32 slot)
 {
@@ -165,6 +166,7 @@ bpf_tail_call_static(void *ctx, const void *map, const __u32 slot)
 		     : "r0", "r1", "r2", "r3", "r4", "r5");
 }
 #endif
+#endif
 
 enum libbpf_pin_type {
 	LIBBPF_PIN_NONE,