dbghelp: Constify some variables.

dlls/dbghelp/dbghelp_private.h

@@ -559,7 +559,7 @@ extern struct symt_function*
                                       unsigned long addr, unsigned long size,
                                       struct symt* type);
 extern BOOL         symt_normalize_function(struct module* module, 
-                                            struct symt_function* func);
+                                            const struct symt_function* func);
 extern void         symt_add_func_line(struct module* module,
                                        struct symt_function* func, 
                                        unsigned source_idx, int line_num, 
@@ -577,7 +577,7 @@ extern struct symt_block*
                                          unsigned pc, unsigned len);
 extern struct symt_block*
                     symt_close_func_block(struct module* module, 
-                                          struct symt_function* func,
+                                          const struct symt_function* func,
                                           struct symt_block* block, unsigned pc);
 extern struct symt_hierarchy_point*
                     symt_add_function_point(struct module* module, 

dlls/dbghelp/symbol.c

@@ -486,7 +486,7 @@ struct symt_block* symt_open_func_block(struct module* module,
 }
 
 struct symt_block* symt_close_func_block(struct module* module, 
-                                         struct symt_function* func,
+                                         const struct symt_function* func,
                                          struct symt_block* block, unsigned pc)
 {
     assert(func);
@@ -518,7 +518,7 @@ struct symt_hierarchy_point* symt_add_function_point(struct module* module,
     return sym;
 }
 
-BOOL symt_normalize_function(struct module* module, struct symt_function* func)
+BOOL symt_normalize_function(struct module* module, const struct symt_function* func)
 {
     unsigned            len;
     struct line_info*   dli;
@@ -771,7 +771,7 @@ static BOOL send_symbol(const struct sym_enum* se, const struct module_pair* pai
     return !se->cb(se->sym_info, se->sym_info->Size, se->user);
 }
 
-static BOOL symt_enum_module(struct module_pair* pair, const regex_t* regex,
+static BOOL symt_enum_module(const struct module_pair* pair, const regex_t* regex,
                              const struct sym_enum* se)
 {
     void*                       ptr;
@@ -792,7 +792,7 @@ static BOOL symt_enum_module(struct module_pair* pair, const regex_t* regex,
     return FALSE;
 }
 
-static inline unsigned where_to_insert(const struct module* module, unsigned high, struct symt_ht* elt)
+static inline unsigned where_to_insert(const struct module* module, unsigned high, const struct symt_ht* elt)
 {
     unsigned    low = 0, mid = high / 2;
     ULONG64     addr;
@@ -848,7 +848,7 @@ static BOOL resort_symbols(struct module* module)
     return module->sortlist_valid = TRUE;
 }
 
-static void symt_get_length(struct symt* symt, ULONG64* size)
+static void symt_get_length(const struct symt* symt, ULONG64* size)
 {
     DWORD       type_index;