SAFE_MACROS: Add SAFE_SETSID()

Signed-off-by: Guangwen Feng <fenggw-fnst@cn.fujitsu.com>
diff --git a/lib/safe_macros.c b/lib/safe_macros.c
index a6b4ff7..3ef9266 100644
--- a/lib/safe_macros.c
+++ b/lib/safe_macros.c
@@ -895,3 +895,16 @@
 
 	return rval;
 }
+
+pid_t safe_setsid(const char *file, const int lineno)
+{
+	pid_t rval;
+
+	rval = setsid();
+	if (rval == -1) {
+		tst_brkm(TBROK | TERRNO, NULL,
+			 "%s:%d: setsid() failed", file, lineno);
+	}
+
+	return rval;
+}