diff --git a/gdb/m68k-pinsn.c b/gdb/m68k-pinsn.c
index f5a9fb50fcc..694a2469d0c 100644
--- a/gdb/m68k-pinsn.c
+++ b/gdb/m68k-pinsn.c
@@ -181,7 +181,7 @@ print_insn_arg (d, buffer, p, addr, stream)
   register int val;
   register int place = d[1];
   int regno;
-  register char *regname;
+  register const char *regname;
   register unsigned char *p1;
   double flval;
   int flt_p;