Make some structures immutable
diff --git a/coders/meta.c b/coders/meta.c
index 8dd5913..971dbba 100644
--- a/coders/meta.c
+++ b/coders/meta.c
@@ -143,14 +143,15 @@
 
 typedef struct _html_code
 {
-  short
+  const short
     len;
+
   const char
     *code,
     val;
 } html_code;
 
-static html_code html_codes[] = {
+static const html_code html_codes[] = {
 #ifdef HANDLE_GT_LT
   { 4,"&lt;",'<' },
   { 4,"&gt;",'>' },
@@ -1757,7 +1758,7 @@
 
 typedef struct _tag_spec
 {
-  short
+  const short
     id;
 
   const char