https://bugs.gentoo.org/452108
 
 common/common.cc | 1 +
 server/thread.cc | 1 +
 2 files changed, 2 insertions(+)

--- a/common/common.cc
+++ b/common/common.cc
@@ -18,6 +18,7 @@
  * Foundation, Inc., 51 Franklin Street, Fifth Floor Boston, MA 02110-1301,  USA
  */
 
+#include <unistd.h>
 #include "../common/common.h"
 #include "../common/i18n.h"
 #include "../common/exception.h"
--- a/server/thread.cc
+++ b/server/thread.cc
@@ -18,6 +18,7 @@
  * Foundation, Inc., 51 Franklin Street, Fifth Floor Boston, MA 02110-1301,  USA
  */
 
+#include <unistd.h>
 #include "thread.h"
 #include "../common/i18n.h"
 #include "../common/exception.h"