virFork: placate static analyzers: ignore pthread_sigmask return value

* src/util/util.c: Include "ignore-value.h".
(virFork): We really do want to ignore pthread_sigmask failure.

src/util/util.c

@@ -69,6 +69,7 @@
 #include "virterror_internal.h"
 #include "logging.h"
 #include "event.h"
+#include "ignore-value.h"
 #include "buf.h"
 #include "util.h"
 #include "memory.h"
@@ -344,7 +345,7 @@ int virFork(pid_t *pid) {
     if (*pid < 0) {
         /* attempt to restore signal mask, but ignore failure, to
            avoid obscuring the fork failure */
-        pthread_sigmask(SIG_SETMASK, &oldmask, NULL);
+        ignore_value (pthread_sigmask(SIG_SETMASK, &oldmask, NULL));
         virReportSystemError(saved_errno,
                              "%s", _("cannot fork child process"));
         goto cleanup;