linux-user: Add support for SO_REUSEPORT

Add support for SO_REUSEPORT, including strace support. SO_REUSEPORT
was introduced relatively recently, since Linux 3.9, so use
'#if defined SO_REUSEPORT'.

Signed-off-by: Yunqiang Su <ysu@wavecomp.com>
Signed-off-by: Aleksandar Markovic <amarkovic@wavecomp.com>
Reviewed-by: Laurent Vivier <laurent@vivier.eu>
Message-Id: <1540904108-30873-4-git-send-email-aleksandar.markovic@rt-rk.com>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index 810a58b..5c16692 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -2061,6 +2061,11 @@
         case TARGET_SO_REUSEADDR:
 		optname = SO_REUSEADDR;
 		break;
+#ifdef SO_REUSEPORT
+        case TARGET_SO_REUSEPORT:
+                optname = SO_REUSEPORT;
+                break;
+#endif
         case TARGET_SO_TYPE:
 		optname = SO_TYPE;
 		break;
@@ -2222,6 +2227,11 @@
         case TARGET_SO_REUSEADDR:
             optname = SO_REUSEADDR;
             goto int_case;
+#ifdef SO_REUSEPORT
+        case TARGET_SO_REUSEPORT:
+            optname = SO_REUSEPORT;
+            goto int_case;
+#endif
         case TARGET_SO_TYPE:
             optname = SO_TYPE;
             goto int_case;