https://sourceware.org/pipermail/gdb-patches/2020-May/168808.html

--- a/gdb/ia64-linux-nat.c
+++ b/gdb/ia64-linux-nat.c
@@ -21,6 +21,7 @@
 #include "defs.h"
 #include "inferior.h"
 #include "target.h"
+#include "gdbarch.h"
 #include "gdbcore.h"
 #include "regcache.h"
 #include "ia64-tdep.h"
-- 
2.26.2