[PATCH bpf-next v1 09/19] selftests/bpf: Fix missing BUILD_BUG_ON() declaration

[Tony Ambardar <tony.ambardar@xxxxxxxxx>]

Explicitly include '<linux/build_bug.h>' to fix errors seen compiling with
gcc targeting mips64el/musl-libc:

  user_ringbuf.c: In function 'test_user_ringbuf_loop':
  user_ringbuf.c:426:9: error: implicit declaration of function 'BUILD_BUG_ON' [-Werror=implicit-function-declaration]
    426 |         BUILD_BUG_ON(total_samples <= c_max_entries);
        |         ^~~~~~~~~~~~
  cc1: all warnings being treated as errors

Fixes: e5a9df51c746 ("selftests/bpf: Add selftests validating the user ringbuf")
Signed-off-by: Tony Ambardar <tony.ambardar@xxxxxxxxx>
---
 tools/testing/selftests/bpf/prog_tests/user_ringbuf.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/tools/testing/selftests/bpf/prog_tests/user_ringbuf.c b/tools/testing/selftests/bpf/prog_tests/user_ringbuf.c
index e51721df14fc..dfff6feac12c 100644
--- a/tools/testing/selftests/bpf/prog_tests/user_ringbuf.c
+++ b/tools/testing/selftests/bpf/prog_tests/user_ringbuf.c
@@ -4,6 +4,7 @@
 #define _GNU_SOURCE
 #include <linux/compiler.h>
 #include <linux/ring_buffer.h>
+#include <linux/build_bug.h>
 #include <pthread.h>
 #include <stdio.h>
 #include <stdlib.h>
-- 
2.34.1