diff --git a/src/alchemy.h b/src/alchemy.h
index af7adf459..46feeb689 100644
--- a/src/alchemy.h
+++ b/src/alchemy.h
@@ -23,6 +23,12 @@ OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 extern "C" {
 #endif
 
+    struct potion_type;
+    struct unit;
+    struct region;
+    struct item_type;
+    struct order;
+    
   enum {
     /* Stufe 1 */
     P_FAST,
diff --git a/src/gmtool.h b/src/gmtool.h
index 0359973b5..4e3570de2 100644
--- a/src/gmtool.h
+++ b/src/gmtool.h
@@ -14,10 +14,12 @@
 #ifdef __cplusplus
 extern "C" {
 #endif
-  struct lua_State;
-  struct selection;
-  struct state;
-  struct region;
+
+    struct lua_State;
+    struct selection;
+    struct state;
+    struct region;
+    struct terrain_type;
 
   int gmmain(int argc, char *argv[]);
   int curses_readline(struct lua_State *L, char *buffer, size_t size,
diff --git a/src/kernel/connection.h b/src/kernel/connection.h
index edbf23bb5..dd168b413 100644
--- a/src/kernel/connection.h
+++ b/src/kernel/connection.h
@@ -25,6 +25,13 @@ OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 extern "C" {
 #endif
 
+    struct attrib;
+    struct attrib_type;
+    struct faction;
+    struct region;
+    struct storage;
+    struct unit;
+    
   extern int nextborder;
 
   typedef struct connection {
diff --git a/src/kernel/equipment.h b/src/kernel/equipment.h
index 9eee8b5d8..619b05193 100644
--- a/src/kernel/equipment.h
+++ b/src/kernel/equipment.h
@@ -24,34 +24,36 @@ OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 #ifdef __cplusplus
 extern "C" {
 #endif
-  struct spell;
+    struct spell;
+    struct item;
+    struct unit;
 
-  typedef struct itemdata {
-    const struct item_type *itype;
-    char *value;
-    struct itemdata *next;
-  } itemdata;
-
-  typedef struct subsetitem {
-    struct equipment *set;
-    float chance;
-  } subsetitem;
-
-  typedef struct subset {
-    float chance;
-    subsetitem *sets;
-  } subset;
-
-  typedef struct equipment {
-    char *name;
-    struct itemdata *items;
-    char *skills[MAXSKILLS];
-    struct spellbook *spellbook;
-    struct subset *subsets;
-    struct equipment *next;
-    void (*callback) (const struct equipment *, struct unit *);
-  } equipment;
+    typedef struct itemdata {
+        const struct item_type *itype;
+        char *value;
+        struct itemdata *next;
+    } itemdata;
 
+    typedef struct subsetitem {
+        struct equipment *set;
+        float chance;
+    } subsetitem;
+    
+    typedef struct subset {
+        float chance;
+        subsetitem *sets;
+    } subset;
+    
+    typedef struct equipment {
+        char *name;
+        struct itemdata *items;
+        char *skills[MAXSKILLS];
+        struct spellbook *spellbook;
+        struct subset *subsets;
+        struct equipment *next;
+        void (*callback) (const struct equipment *, struct unit *);
+    } equipment;
+    
   extern struct equipment *create_equipment(const char *eqname);
   extern struct equipment *get_equipment(const char *eqname);
 
diff --git a/src/kernel/item.h b/src/kernel/item.h
index bbb2653ad..790911ba6 100644
--- a/src/kernel/item.h
+++ b/src/kernel/item.h
@@ -26,13 +26,15 @@ OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 extern "C" {
 #endif
 
-  struct unit;
-  struct attrib;
-  struct attrib_type;
-  struct region;
-  struct resource_type;
-  struct locale;
-  struct troop;
+    struct unit;
+    struct attrib;
+    struct attrib_type;
+    struct region;
+    struct resource_type;
+    struct locale;
+    struct troop;
+    struct item;
+    struct order;
 
   typedef struct item {
     struct item *next;
diff --git a/src/kernel/plane.h b/src/kernel/plane.h
index 1c7e505dc..e28e67266 100644
--- a/src/kernel/plane.h
+++ b/src/kernel/plane.h
@@ -22,6 +22,10 @@ OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 extern "C" {
 #endif
 
+    struct region;
+    struct plane;
+    struct storage;
+
 #define PFL_NOCOORDS        1   /* not in use */
 #define PFL_NORECRUITS      2
 #define PFL_NOALLIANCES     4
diff --git a/src/kernel/pool.h b/src/kernel/pool.h
index d6f4766c6..6c47a5c14 100644
--- a/src/kernel/pool.h
+++ b/src/kernel/pool.h
@@ -22,6 +22,10 @@ OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 extern "C" {
 #endif
 
+    struct unit;
+    struct resource_type;
+    struct region;
+
 /* bitfield values for get/use/change operations */
 #define GET_SLACK      0x01
 #define GET_RESERVE    0x02
diff --git a/src/kernel/save.h b/src/kernel/save.h
index 775624f11..2c119a5eb 100644
--- a/src/kernel/save.h
+++ b/src/kernel/save.h
@@ -22,6 +22,13 @@ OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 extern "C" {
 #endif
 
+    struct attrib;
+    struct item;
+    struct storage;
+    struct spell;
+    struct spellbook;
+    struct unit;
+    
   typedef struct gamedata {
     struct storage *store;
     int version;
diff --git a/src/kernel/spell.h b/src/kernel/spell.h
index 40404b4d2..7d10df60b 100644
--- a/src/kernel/spell.h
+++ b/src/kernel/spell.h
@@ -22,7 +22,14 @@ OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 extern "C" {
 #endif
 
-  struct castorder;
+    struct castorder;
+    struct unit;
+    struct region;
+    struct spell;
+    struct spell_component;
+    struct quicklist;
+    struct attrib_type;
+
   typedef int (*spell_f)(struct castorder * co);
   typedef void(*fumble_f)(const struct castorder * co);
 
diff --git a/src/laws.h b/src/laws.h
index 0d86c4225..8ab6ea469 100755
--- a/src/laws.h
+++ b/src/laws.h
@@ -22,17 +22,24 @@ OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 extern "C" {
 #endif
 
-  extern int writepasswd(void);
-  void demographics(void);
-  void update_guards(void);
-  void update_subscriptions(void);
-  void deliverMail(struct faction *f, struct region *r, struct unit *u,
-    const char *s, struct unit *receiver);
+    struct unit;
+    struct region;
+    struct building;
+    struct faction;
+    struct order;
+    struct attrib_type;
 
-  bool renamed_building(const struct building * b);
-  int rename_building(struct unit * u, struct order * ord, struct building * b, const char *name);
-  void get_food(struct region * r);
-  extern int can_contact(const struct region *r, const struct unit *u, const struct unit *u2);
+    int writepasswd(void);
+    void demographics(void);
+    void update_guards(void);
+    void update_subscriptions(void);
+    void deliverMail(struct faction *f, struct region *r, struct unit *u,
+                     const char *s, struct unit *receiver);
+
+    bool renamed_building(const struct building * b);
+    int rename_building(struct unit * u, struct order * ord, struct building * b, const char *name);
+    void get_food(struct region * r);
+    int can_contact(const struct region *r, const struct unit *u, const struct unit *u2);
 
 /* eressea-specific. put somewhere else, please. */
   void processorders(void);
diff --git a/src/move.h b/src/move.h
index 4b0a9e4c7..27704d4a4 100644
--- a/src/move.h
+++ b/src/move.h
@@ -26,6 +26,8 @@ extern "C" {
 #endif
 
     struct unit;
+    struct region;
+    struct region_list;
     struct ship;
     struct building_type;
 
diff --git a/src/spells/shipcurse.h b/src/spells/shipcurse.h
index ab60d7232..551d1a920 100644
--- a/src/spells/shipcurse.h
+++ b/src/spells/shipcurse.h
@@ -20,15 +20,19 @@
 extern "C" {
 #endif
 
-  struct locale;
-  struct message;
-  extern struct message *cinfo_ship(const void *obj, objtype_t typ,
-    const struct curse *c, int self);
-  extern void register_shipcurse(void);
-  extern struct curse *shipcurse_flyingship(struct ship *sh, struct unit *mage,
-    float power, int duration);
-  int levitate_ship(struct ship *sh, struct unit *mage, float power,
-    int duration);
+    struct locale;
+    struct message;
+    struct ship;
+    struct unit;
+    struct curse;
+
+    struct message *cinfo_ship(const void *obj, objtype_t typ,
+                               const struct curse *c, int self);
+    void register_shipcurse(void);
+    struct curse *shipcurse_flyingship(struct ship *sh, struct unit *mage,
+                                       float power, int duration);
+    int levitate_ship(struct ship *sh, struct unit *mage, float power,
+                      int duration);
 
 #ifdef __cplusplus
 }