https://bugs.gentoo.org/421607

 evocommon.h:468:29: error: 'usleep' was not declared in this scope
 
 libevocosm/evocommon.h | 4 ++++
 1 file changed, 4 insertions(+)

--- a/libevocosm/evocommon.h
+++ b/libevocosm/evocommon.h
@@ -54,6 +54,10 @@
 #undef min
 #endif
 
+#if !defined(_MSC_VER)
+#include "unistd.h"
+#endif
+
 namespace libevocosm
 {
     //! The random number generator used by Evocosm