diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 964a01d6f1b..a708c3f8d73 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,8 @@
+2020-01-24  Christian Biesinger  <cbiesinger@google.com>
+
+	* arm-nbsd-nat.c: Define _KERNTYPES to get the declaration of
+	register_t.
+
 2020-01-24  Christian Biesinger  <cbiesinger@google.com>
 
 	* aarch64-fbsd-tdep.c (aarch64_fbsd_iterate_over_regset_sections):
diff --git a/gdb/arm-nbsd-nat.c b/gdb/arm-nbsd-nat.c
index 00f919194b9..33ae790063f 100644
--- a/gdb/arm-nbsd-nat.c
+++ b/gdb/arm-nbsd-nat.c
@@ -17,6 +17,8 @@
    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
 
+/* We define this to get types like register_t.  */
+#define _KERNTYPES
 #include "defs.h"
 #include "gdbcore.h"
 #include "inferior.h"