https://bugs.gentoo.org/671722

--- a/mysys/mf_iocache2.c
+++ b/mysys/mf_iocache2.c
@@ -22,6 +22,7 @@
 #include <m_string.h>
 #include <stdarg.h>
 #include <m_ctype.h>
+#include "mysql/psi/mysql_file.h"
 
 /*
   Copy contents of an IO_CACHE to a file.