mrb_read_irep should take const char *

Signed-off-by: Patrick Hogan <pbhogan@gmail.com>

include/mruby/dump.h

@@ -11,7 +11,7 @@
 int mrb_dump_irep(mrb_state*,int,FILE*);
 int mrb_load_irep(mrb_state*,FILE*);
 int mrb_load_irep_offset(mrb_state*,FILE*,long);
-int mrb_read_irep(mrb_state*,char*);
+int mrb_read_irep(mrb_state*,const char*);
 
 int mrb_bdump_irep(mrb_state *mrb, int n, FILE *f,const char *initname);
 

src/load.c

@@ -495,7 +495,7 @@ error_exit:
 }
 
 int
-mrb_read_irep(mrb_state *mrb, char *bin)
+mrb_read_irep(mrb_state *mrb, const char *bin)
 {
   int ret = MRB_DUMP_OK, i, n, nirep, sirep;
   uint32_t len;