perf tools: Move event synthesizing routines to separate header

Those are the only routines using the perf_event__handler_t typedef and
are all related, so move to a separate header to reduce the header
dependency tree, lots of places were getting event.h and even stdio.h,
limits.h indirectly, so fix those as well.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/n/tip-yvx9u1mf7baq6cu1abfhbqgs@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
diff --git a/tools/perf/util/bpf-event.c b/tools/perf/util/bpf-event.c
index 7a3d4b1..f7ed5d1 100644
--- a/tools/perf/util/bpf-event.c
+++ b/tools/perf/util/bpf-event.c
@@ -16,6 +16,7 @@
 #include "map.h"
 #include "evlist.h"
 #include "record.h"
+#include "util/synthetic-events.h"
 
 #define ptr_to_u64(ptr)    ((__u64)(unsigned long)(ptr))