diff --git a/mjit.c b/mjit.c
index 36ffae4bf2..43449851ec 100644
--- a/mjit.c
+++ b/mjit.c
@@ -381,7 +381,14 @@ start_process(const char *path, char *const *argv)
         }
         dev_null = rb_cloexec_open(ruby_null_device, O_WRONLY, 0);
 
+#ifdef __GNUC__
+# pragma GCC diagnostic push
+# pragma GCC diagnostic ignored "-Wdeprecated-declarations"
+#endif
         if ((pid = vfork()) == 0) {
+#ifdef __GNUC__
+# pragma GCC diagnostic pop
+#endif
             umask(0077);
             if (mjit_opts.verbose == 0) {
                 /* CC can be started in a thread using a file which has been
diff --git a/process.c b/process.c
index d1d33dd1b0..956db995ca 100644
--- a/process.c
+++ b/process.c
@@ -3867,6 +3867,10 @@ retry_fork_async_signal_safe(int *status, int *ep,
     while (1) {
         prefork();
         disable_child_handler_before_fork(&old);
+#ifdef __GNUC__
+# pragma GCC diagnostic push
+# pragma GCC diagnostic ignored "-Wdeprecated-declarations"
+#endif
 #ifdef HAVE_WORKING_VFORK
         if (!has_privilege())
             pid = vfork();
@@ -3874,6 +3878,9 @@ retry_fork_async_signal_safe(int *status, int *ep,
             pid = fork();
 #else
         pid = fork();
+#endif
+#ifdef __GNUC__
+# pragma GCC diagnostic pop
 #endif
         if (pid == 0) {/* fork succeed, child process */
             int ret;
@@ -3943,7 +3950,14 @@ rb_fork_ruby(int *status)
 	prefork();
 	disable_child_handler_before_fork(&old);
 	before_fork_ruby();
+#ifdef __GNUC__
+# pragma GCC diagnostic push
+# pragma GCC diagnostic ignored "-Wdeprecated-declarations"
+#endif
 	pid = fork();
+#ifdef __GNUC__
+# pragma GCC diagnostic pop
+#endif
 	err = errno;
 	after_fork_ruby();
 	disable_child_handler_fork_parent(&old); /* yes, bad name */