https://bugs.gentoo.org/580816

include headers needed by targets

--- b/uml_net/ethertap.c
+++ a/uml_net/ethertap.c
@@ -13,6 +13,7 @@
 #include <sys/stat.h>
 #include <sys/ioctl.h>
 #include <net/if.h>
+#include <sys/select.h>
 #include "host.h"
 #include "output.h"
 

for major/minor macros

--- b/uml_net/host.c
+++ a/uml_net/host.c
@@ -10,6 +10,7 @@
 #include <ctype.h>
 #include <sys/wait.h>
 #include <sys/stat.h>
+#include <sys/sysmacros.h>
 #include "output.h"
 #include "host.h"