[tip:perf/urgent] tools lib bpf: Fix the build by adding a missing stdarg.h include

[tip-bot for Arnaldo Carvalho de Melo]

Commit-ID:  dfcbc2f2994b8a3af3605a26dc29c07ad7378bf4
Gitweb:     https://git.kernel.org/tip/dfcbc2f2994b8a3af3605a26dc29c07ad7378bf4
Author:     Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
AuthorDate: Mon, 11 Mar 2019 17:07:52 -0300
Committer:  Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
CommitDate: Mon, 11 Mar 2019 17:14:31 -0300

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@xxxxxxxxxx>
Cc: Daniel Borkmann <daniel@xxxxxxxxxxxxx>
Cc: Jakub Kicinski <jakub.kicinski@xxxxxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Quentin Monnet <quentin.monnet@xxxxxxxxxxxxx>
Cc: Stanislav Fomichev <sdf@xxxxxxxxxx>
Cc: Yonghong Song <yhs@xxxxxx>
Fixes: a8a1f7d09cfc ("libbpf: fix libbpf_print")
Link: https://lkml.kernel.org/n/tip-5270n2quu2gqz22o7itfdx00@xxxxxxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
 tools/lib/bpf/libbpf.h | 1 +
 1 file changed, 1 insertion(+)

diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
index b4652aa1a58a..aa1521a51687 100644
--- 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>