[PATCH] hurd: add missing include

[Samuel Thibault]

gdb/Changelog:

2020-05-29  Samuel Thibault  <samuel.thiba...@ens-lyon.org>

        * gnu-nat.c: Include "gdbarch.h".

diff --git a/gdb/gnu-nat.c b/gdb/gnu-nat.c
index 3b438a9a43..78e9ab7f71 100644
--- a/gdb/gnu-nat.c
+++ b/gdb/gnu-nat.c
@@ -64,6 +64,7 @@ extern "C"
 #include "language.h"
 #include "target.h"
 #include "gdbsupport/gdb_wait.h"
+#include "gdbarch.h"
 #include "gdbcmd.h"
 #include "gdbcore.h"
 #include "gdbthread.h"