Added FD_CLOEXEC flag to client/server socket file descriptors

runtime/bin/socket_macos.cc

Index: runtime/bin/socket_macos.cc
diff --git a/runtime/bin/socket_macos.cc b/runtime/bin/socket_macos.cc
index 5e830ff2d233c830614e6823e86805f71a2c0b4f..32db433acfc9beac929cb42432869ce9c3053bc1 100644
--- a/runtime/bin/socket_macos.cc
+++ b/runtime/bin/socket_macos.cc
@@ -29,6 +29,7 @@ intptr_t Socket::CreateConnect(const char* host, const intptr_t port) {
     return -1;
   }
 
+  FDUtils::SetCloseOnExec(fd);
   FDUtils::SetNonBlocking(fd);
 
   server = gethostbyname(host);
@@ -187,6 +188,8 @@ intptr_t ServerSocket::CreateBindListen(const char* host,
     return -1;
   }
 
+  FDUtils::SetCloseOnExec(fd);
+
   int optval = 1;
   TEMP_FAILURE_RETRY(
       setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &optval, sizeof(optval)));