--- gc-7.6.0.orig/pthread_stop_world.c
+++ gc-7.6.0/pthread_stop_world.c
@@ -45,6 +45,7 @@
 #include <semaphore.h>
 #include <errno.h>
 #include <unistd.h>
+#include <sys/select.h>
 #include "atomic_ops.h"
 
 /* It's safe to call original pthread_sigmask() here.   */