Make a few constant globals actually const.

This means the .data and .bss sections are empty, a good thing
in a shared library (see #98).

builtin.c

@@ -1,6 +1,5 @@
 #include <string.h>
 #include "builtin.h"
-#include "bytecode.h"
 #include "compile.h"
 #include "parser.h"
 #include "locfile.h"
@@ -469,7 +468,7 @@ static jv f_error(jv input, jv msg) {
   return jv_invalid_with_msg(msg);
 }
 
-static struct cfunction function_list[] = {
+static const struct cfunction function_list[] = {
   {(cfunction_ptr)f_plus, "_plus", 3},
   {(cfunction_ptr)f_negate, "_negate", 1},
   {(cfunction_ptr)f_minus, "_minus", 3},
@@ -501,9 +500,6 @@ static struct cfunction function_list[] = {
   {(cfunction_ptr)f_format, "format", 2},
 };
 
-static struct symbol_table cbuiltins = 
-  {function_list, sizeof(function_list)/sizeof(function_list[0])};
-
 struct bytecoded_builtin { const char* name; block code; };
 static block bind_bytecoded_builtins(block b) {
   block builtins = gen_noop();
@@ -537,7 +533,7 @@ static block bind_bytecoded_builtins(block b) {
   return block_bind(builtins, b, OP_IS_CALL_PSEUDO);
 }
 
-static const char* jq_builtins[] = {
+static const char* const jq_builtins[] = {
   "def map(f): [.[] | f];",
   "def select(f): if f then . else empty end;",
   "def sort_by(f): _sort_by_impl(map([f]));",
@@ -564,5 +560,5 @@ block builtins_bind(block b) {
     locfile_free(&src);
   }
   b = bind_bytecoded_builtins(b);
-  return gen_cbinding(&cbuiltins, b);
+  return gen_cbinding(function_list, sizeof(function_list)/sizeof(function_list[0]), b);
 }

compile.c

@@ -30,7 +30,7 @@ struct inst {
     uint16_t intval;
     struct inst* target;
     jv constant;
-    struct cfunction* cfunc;
+    const struct cfunction* cfunc;
   } imm;
 
   location source;
@@ -377,10 +377,10 @@ block gen_cond(block cond, block iftrue, block iffalse) {
                               BLOCK(gen_op_simple(POP), iffalse)));
 }
 
-block gen_cbinding(struct symbol_table* t, block code) {
-  for (int cfunc=0; cfunc<t->ncfunctions; cfunc++) {
+block gen_cbinding(const struct cfunction* cfunctions, int ncfunctions, block code) {
+  for (int cfunc=0; cfunc<ncfunctions; cfunc++) {
     inst* i = inst_new(CLOSURE_CREATE_C);
-    i->imm.cfunc = &t->cfunctions[cfunc];
+    i->imm.cfunc = &cfunctions[cfunc];
     i->symbol = strdup(i->imm.cfunc->name);
     code = block_bind(inst_block(i), code, OP_IS_CALL_PSEUDO);
   }

compile.h

@@ -7,6 +7,7 @@
 
 struct bytecode;
 struct symbol_table;
+struct cfunction;
 
 struct inst;
 typedef struct inst inst;
@@ -41,7 +42,7 @@ block gen_or(block a, block b);
 
 block gen_cond(block cond, block iftrue, block iffalse);
 
-block gen_cbinding(struct symbol_table* functions, block b);
+block gen_cbinding(const struct cfunction* functions, int nfunctions, block b);
 
 void block_append(block* b, block b2);
 block block_join(block a, block b);

jv_parse.c

@@ -283,7 +283,7 @@ static chclass classify(char c) {
 }
 
 
-static presult OK = "output produced";
+static const presult OK = "output produced";
 
 static int check_done(struct jv_parser* p, jv* out) {
   if (p->stackpos == 0 && jv_is_valid(p->next)) {
@@ -341,7 +341,7 @@ static pfunc scan(struct jv_parser* p, char ch, jv* out) {
   return answer;
 }
 
-static unsigned char UTF8_BOM[] = {0xEF,0xBB,0xBF};
+static const unsigned char UTF8_BOM[] = {0xEF,0xBB,0xBF};
 
 void jv_parser_set_buf(struct jv_parser* p, const char* buf, int length, int is_partial) {
   assert((p->curr_buf == 0 || p->curr_buf_pos == p->curr_buf_length)

jv_print.c

@@ -12,10 +12,10 @@
 
 // Colour table. See http://en.wikipedia.org/wiki/ANSI_escape_code#Colors
 // for how to choose these.
-static jv_kind colour_kinds[] = 
+static const jv_kind colour_kinds[] = 
   {JV_KIND_NULL,   JV_KIND_FALSE, JV_KIND_TRUE, JV_KIND_NUMBER,
    JV_KIND_STRING, JV_KIND_ARRAY, JV_KIND_OBJECT};
-static const char* colours[] =
+static const char* const colours[] =
   {COL("30;1"),    COL("0"),      COL("0"),     COL("0"),
    COL("32"),      COL("37"),     COL("37")};
 #define FIELD_COLOUR COL("34;1")