Bug: https://bugs.gentoo.org/897938
--- a/src/getopt.c
+++ b/src/getopt.c
@@ -52,6 +52,7 @@ char *alloca ();
 #endif
 
 #include <stdio.h>
+#include <string.h>
 
 /* Comment out all this code if we are using the GNU C Library, and are not
    actually compiling the library itself.  This code is part of the GNU C