core, api: use "const char *" variables for result of string functions with const parameter

src/gui/gui-bar-item-custom.c

@@ -138,7 +138,8 @@ gui_bar_item_custom_search (const char *item_name)
 struct t_gui_bar_item_custom *
 gui_bar_item_custom_search_with_option_name (const char *option_name)
 {
-    char *item_name, *pos_option;
+    const char *pos_option;
+    char *item_name;
     struct t_gui_bar_item_custom *ptr_item;
 
     if (!option_name)

src/gui/gui-bar.c

@@ -515,7 +515,8 @@ gui_bar_search (const char *name)
 struct t_gui_bar *
 gui_bar_search_with_option_name (const char *option_name)
 {
-    char *bar_name, *pos_option;
+    const char *pos_option;
+    char *bar_name;
     struct t_gui_bar *ptr_bar;
 
     if (!option_name)

src/gui/gui-chat.c

@@ -118,8 +118,8 @@ gui_chat_init (void)
 void
 gui_chat_prefix_build (void)
 {
-    const char *ptr_prefix;
-    char prefix[512], *pos_color;
+    const char *ptr_prefix, *pos_color;
+    char prefix[512];
     int prefix_color[GUI_CHAT_NUM_PREFIXES] =
         { GUI_COLOR_CHAT_PREFIX_ERROR, GUI_COLOR_CHAT_PREFIX_NETWORK,
           GUI_COLOR_CHAT_PREFIX_ACTION, GUI_COLOR_CHAT_PREFIX_JOIN,

src/gui/gui-color.c

@@ -254,8 +254,8 @@ gui_color_get_custom (const char *color_name)
     static char color[32][96];
     static int index_color = 0;
     char color_fg[32], color_bg[32];
-    char *pos_delim, *str_fg, *pos_bg, *error, *color_attr;
-    const char *ptr_color_name;
+    char *str_fg, *error, *color_attr;
+    const char *ptr_color_name, *pos_delim, *pos_bg;
 
     /* attribute or other color name (GUI dependent) */
     index_color = (index_color + 1) % 32;

src/gui/gui-filter.c

@@ -366,8 +366,8 @@ gui_filter_new (int enabled, const char *name, const char *buffer_name,
 {
     struct t_gui_filter *new_filter;
     regex_t *regex1, *regex2;
-    char *pos_tab, *regex_prefix, buf[512], str_error[1024];
-    const char *ptr_start_regex, *pos_regex_message;
+    char *regex_prefix, buf[512], str_error[1024];
+    const char *ptr_start_regex, *pos_regex_message, *pos_tab;
     int rc;
 
     if (!name || !buffer_name || !tags || !regex)

src/gui/gui-key.c

@@ -1076,7 +1076,7 @@ gui_key_set_area_type_name (const char *area,
                             int *area_type, char **area_name)
 {
     int focus, length;
-    char *pos_end;
+    const char *pos_end;
 
     for (focus = 0; focus < GUI_KEY_NUM_FOCUS; focus++)
     {