perf tools: Add missing sigqueue() prototype for systems lacking it

Commit-ID:  748fe0889c1ff12d378946bd5326e8ee8eacf5cf
Gitweb:     https://git.kernel.org/tip/748fe0889c1ff12d378946bd5326e8ee8eacf5cf
Author:     Arnaldo Carvalho de Melo <[email protected]>
AuthorDate: Tue, 11 Dec 2018 15:48:47 -0300
Committer:  Arnaldo Carvalho de Melo <[email protected]>
CommitDate: Tue, 18 Dec 2018 12:23:56 -0300

perf tools: Add missing sigqueue() prototype for systems lacking it

There are systems such as the Android NDK API level 24 has the sigqueue() function but doesn't provide a prototype, adding noise to the build:

util/evlist.c: In function 'perf_evlist__prepare_workload':
util/evlist.c:1494:4: warning: implicit declaration of function 'sigqueue' [-Wimplicit-function-declaration]
if (sigqueue(getppid(), SIGUSR1, val))
^
util/evlist.c:1494:4: warning: nested extern declaration of 'sigqueue' [-Wnested-externs]

Define a LACKS_SIGQUEUE_PROTOTYPE define so that code needing that can get a prototype.

Checked in the bionic git repo to be available since level 23:

https://android.googlesource.com/platform/bionic/+/master/libc/include/signal.h#123

  int sigqueue(pid_t __pid, int __signal, const union sigval __value) __INTRODUCED_IN(23);

---
 tools/perf/Makefile.config | 1 +
 tools/perf/util/evlist.c   | 4 ++++
 2 files changed, 5 insertions(+)

index b66f97a04b12..265a9225e5fc 100644
@@ -294,6 +294,7 @@ ifndef NO_BIONIC
   $(call feature_check,bionic)
   ifeq ($(feature-bionic), 1)
     BIONIC := 1
+    CFLAGS += -DLACKS_SIGQUEUE_PROTOTYPE
     EXTLIBS := $(filter-out -lrt,$(EXTLIBS))
     EXTLIBS := $(filter-out -lpthread,$(EXTLIBS))
   endif

index e90575192209..8c902276d4b4 100644
@@ -34,6 +34,10 @@
 #include <linux/log2.h>
 #include <linux/err.h>
 
+#ifdef LACKS_SIGQUEUE_PROTOTYPE
+int sigqueue(pid_t pid, int sig, const union sigval value);
+#endif
+
 #define FD(e, x, y) (*(int *)xyarray__entry(e->fd, x, y))
 #define SID(e, x, y) xyarray__entry(e->sample_id, x, y)