tools lib bpf: Fix the build by adding a missing stdarg.h include

The libbpf_print_fn_t typedef uses va_list without including the header
where that type is defined, stdarg.h, breaking in places where we're
unlucky for that type not to be already defined by some previously
included header.

Noticed while building on fedora 24 cross building tools/perf to the ARC
architecture using the uClibc C library:

  28 fedora:24-x-ARC-uClibc   : FAIL arc-linux-gcc (ARCompact ISA Linux uClibc toolchain 2017.09-rc2) 7.1.1 20170710

    CC       /tmp/build/perf/tests/llvm.o
  In file included from tests/llvm.c:3:0:
  /git/linux/tools/lib/bpf/libbpf.h:57:20: error: unknown type name 'va_list'
        const char *, va_list ap);
                      ^~~~~~~
  /git/linux/tools/lib/bpf/libbpf.h:59:34: error: unknown type name 'libbpf_print_fn_t'
   LIBBPF_API void libbpf_set_print(libbpf_print_fn_t fn);
                                    ^~~~~~~~~~~~~~~~~
  mv: cannot stat '/tmp/build/perf/tests/.llvm.o.tmp': No such file or directory

Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Jakub Kicinski <jakub.kicinski@netronome.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Quentin Monnet <quentin.monnet@netronome.com>
Cc: Stanislav Fomichev <sdf@google.com>
Cc: Yonghong Song <yhs@fb.com>
Fixes: a8a1f7d09cfc ("libbpf: fix libbpf_print")
Link: https://lkml.kernel.org/n/tip-5270n2quu2gqz22o7itfdx00@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
index b4652aa1a58adf6d8a42c70467d31e5d434f74f4..aa1521a51687bf4281c3de297ae4de5e03706371 100644 (file)
--- a/tools/lib/bpf/libbpf.h
+++ b/tools/lib/bpf/libbpf.h
@@ -10,6 +10,7 @@
 #ifndef __LIBBPF_LIBBPF_H
 #define __LIBBPF_LIBBPF_H
 
+#include <stdarg.h>
 #include <stdio.h>
 #include <stdint.h>
 #include <stdbool.h>