diff --git a/include/asterisk.h b/include/asterisk.h
index d4b2f03917..da70e8a8c4 100644
--- a/include/asterisk.h
+++ b/include/asterisk.h
@@ -68,12 +68,6 @@ void ast_event_init(void);          /*!< Provided by event.c */
 int ast_device_state_engine_init(void); /*!< Provided by devicestate.c */
 int astobj2_init(void);				/*! Provided by astobj2.c */
 
-/* Many headers need 'ast_channel' to be defined */
-struct ast_channel;
-
-/* Many headers need 'ast_module' to be defined */
-struct ast_module;
-
 /*!
  * \brief Reload asterisk modules.
  * \param name the name of the module to reload
diff --git a/include/asterisk/abstract_jb.h b/include/asterisk/abstract_jb.h
index 1bd9dc84dd..4a41c8c2ca 100644
--- a/include/asterisk/abstract_jb.h
+++ b/include/asterisk/abstract_jb.h
@@ -36,7 +36,6 @@
 extern "C" {
 #endif
 
-struct ast_channel;
 struct ast_frame;
 
 /* Configuration flags */
diff --git a/include/asterisk/compat.h b/include/asterisk/compat.h
index d918cd7075..19ae6e9b14 100644
--- a/include/asterisk/compat.h
+++ b/include/asterisk/compat.h
@@ -176,4 +176,14 @@ typedef unsigned int	u_int32_t;
 typedef unsigned long long uint64_t;
 #endif
 
+/*! \brief
+ * Definition of various structures that many asterisk files need,
+ * but only because they need to know that the type exists.
+ *
+ * We can move them to a different global header if necessary.
+ */
+struct ast_channel;
+struct ast_frame;
+struct ast_module;
+
 #endif
diff --git a/include/asterisk/lock.h b/include/asterisk/lock.h
index 16ce5bb675..055ec84c82 100644
--- a/include/asterisk/lock.h
+++ b/include/asterisk/lock.h
@@ -1185,8 +1185,6 @@ AST_INLINE_API(int ast_atomic_dec_and_test(volatile int *p),
 #define ast_channel_trylock(x)		ast_mutex_trylock(&x->lock_dont_use)
 #else
 
-struct ast_channel;
-
 /*! \brief Lock AST channel (and print debugging output)
 \note You need to enable DEBUG_CHANNEL_LOCKS for this function */
 int ast_channel_lock(struct ast_channel *chan);
diff --git a/utils/extconf.c b/utils/extconf.c
index 0e40718334..caed904780 100644
--- a/utils/extconf.c
+++ b/utils/extconf.c
@@ -1835,8 +1835,6 @@ AST_INLINE_API(int ast_atomic_dec_and_test(volatile int *p),
 #define ast_channel_trylock(x)		ast_mutex_trylock(&x->lock)
 #else
 
-struct ast_channel;
-
 /*! \brief Lock AST channel (and print debugging output)
 \note You need to enable DEBUG_CHANNEL_LOCKS for this function */
 int ast_channel_lock(struct ast_channel *chan);