perf config: Make perf_config_system() global

Make perf_config_system global, it will be used outside the config.c
object in the following patches.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexei Budankov <abudankov@huawei.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Michael Petlan <mpetlan@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lore.kernel.org/lkml/20210102220441.794923-6-jolsa@kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/config.c

@@ -521,7 +521,7 @@ static int perf_env_bool(const char *k, int def)
 	return v ? perf_config_bool(k, v) : def;
 }
 
-static int perf_config_system(void)
+int perf_config_system(void)
 {
 	return !perf_env_bool("PERF_CONFIG_NOSYSTEM", 0);
 }

tools/perf/util/config.h

@@ -38,6 +38,7 @@ int perf_config_bool(const char *, const char *);
 int config_error_nonbool(const char *);
 const char *perf_etc_perfconfig(void);
 const char *perf_home_perfconfig(void);
+int perf_config_system(void);
 
 struct perf_config_set *perf_config_set__new(void);
 struct perf_config_set *perf_config_set__load_file(const char *file);