fix gcc 10 compatibility

s/cmake-init

@@ -48,6 +48,7 @@ fi
 shift 1
 done
 
+git submodule update --init
 ROOT=$(git rev-parse --show-toplevel)
 [ -z $BUILD ] && BUILD=Debug
 [ -z "$CC" ] && [ ! -z `which clang` ] && CC="clang"

src/kernel/connection.h

@@ -126,7 +126,7 @@ extern "C" {
     extern struct attrib_type at_countdown;
 
     /* game-specific callbacks */
-    void(*border_convert_cb) (struct connection * con, struct attrib * attr);
+    extern void(*border_convert_cb) (struct connection * con, struct attrib * attr);
 
     const char * border_name(const struct connection *co,
         const struct region * r, const struct faction * f, int flags);

src/kernel/race.h

@@ -86,6 +86,7 @@ extern "C" {
 
 #define MAX_START_RACE RC_ORC
 
+    extern struct race *races;
     extern int num_races;
     extern const char *racenames[MAXRACES];
 
@@ -151,7 +152,6 @@ extern "C" {
     const struct race *findrace(const char *, const struct locale *);
 
     struct race_list *get_familiarraces(void);
-    struct race *races;
     const struct race *get_race(race_t rt);
     /** TODO: compatibility hacks: **/
     race_t old_race(const struct race *);

src/prefix.h

@@ -6,9 +6,10 @@
 #ifdef __cplusplus
 extern "C" {
 #endif
+    extern char **race_prefixes;
+    /* zero-terminated array of valid prefixes */
 
     int add_raceprefix(const char *);
-    char **race_prefixes; /* zero-terminated array of valid prefixes */
     void free_prefixes(void);
 
 #ifdef __cplusplus

src/util/message.h

@@ -11,8 +11,6 @@ extern "C" {
 #define MT_NEW_END ((const char *)0)
 #define MAXSECTIONS 16
 
-    extern char *sections[MAXSECTIONS];
-
     typedef struct arg_type {
         struct arg_type *next;
         variant_type vtype;
@@ -44,6 +42,9 @@ extern "C" {
         variant args[]);
     /* msg_create(&mt_simplesentence, "enno", "eats", "chocolate", &locale_de);
      * parameters must be in the same order as they were for mt_new! */
+    
+    extern char *sections[MAXSECTIONS];
+    extern void(*msg_log_create) (const struct message * msg);
 
     void msg_release(struct message *msg);
     struct message *msg_addref(struct message *msg);
@@ -62,7 +63,6 @@ extern "C" {
         variant(*copy_arg) (variant), variant_type);
     arg_type *find_argtype(const char *name);
 
-    void(*msg_log_create) (const struct message * msg);
 
 #ifdef __cplusplus
 }