diff --git a/kernel/log.cc b/kernel/log.cc
index 3293a5eae..158dd6f86 100644
--- a/kernel/log.cc
+++ b/kernel/log.cc
@@ -23,6 +23,7 @@
 
 #if !defined(_WIN32) || defined(__MINGW32__)
 #  include <sys/time.h>
+#  include <unistd.h>
 #endif
 
 #if defined(YOSYS_ENABLE_DLOPEN)