diff --git a/include/libwebsockets.h b/include/libwebsockets.h
index 7fceb9b6e..8be5a2f65 100644
--- a/include/libwebsockets.h
+++ b/include/libwebsockets.h
@@ -41,6 +41,11 @@ extern "C" {
 
 #include "lws_config.h"
 
+/* place for one-shot opaque forward references */
+
+struct lws_sequencer;
+struct lws_dsh;
+
 /*
  * CARE: everything using cmake defines needs to be below here
  */
diff --git a/include/libwebsockets/abstract/abstract.h b/include/libwebsockets/abstract/abstract.h
index 7a84b90e2..c3b65bced 100644
--- a/include/libwebsockets/abstract/abstract.h
+++ b/include/libwebsockets/abstract/abstract.h
@@ -76,7 +76,7 @@ typedef struct lws_abs {
 	const struct lws_abs_transport	*at;
 	const lws_token_map_t		*at_tokens;
 
-	lws_seq_t			*seq;
+	struct lws_sequencer		*seq;
 	void				*opaque_user_data;
 
 	/*
diff --git a/include/libwebsockets/lws-client.h b/include/libwebsockets/lws-client.h
index 2461b9b75..c2e40a232 100644
--- a/include/libwebsockets/lws-client.h
+++ b/include/libwebsockets/lws-client.h
@@ -50,8 +50,6 @@ enum lws_client_connect_ssl_connection_flags {
 		 * */
 };
 
-typedef struct lws_sequencer lws_seq_t;
-
 /** struct lws_client_connect_info - parameters to connect with when using
  *				    lws_client_connect_via_info() */
 
@@ -122,7 +120,7 @@ struct lws_client_connect_info {
 	 *           tokens
 	 */
 
-	lws_seq_t *seq;
+	struct lws_sequencer *seq;
 	/**< NULL, or an lws_seq_t that wants to be given messages about
 	 * this wsi's lifecycle as it connects, errors or closes.
 	 */
diff --git a/include/libwebsockets/lws-dsh.h b/include/libwebsockets/lws-dsh.h
index 664e89fc5..137a6089d 100644
--- a/include/libwebsockets/lws-dsh.h
+++ b/include/libwebsockets/lws-dsh.h
@@ -42,8 +42,6 @@
  * All management structures exist inside the allocated buffer.
  */
 
-typedef struct lws_dsh lws_dsh_t;
-
 /**
  * lws_dsh_create() - Allocate a DSH buffer
  *
@@ -64,7 +62,7 @@ typedef struct lws_dsh lws_dsh_t;
  *
  * Returns an opaque pointer to the dsh, or NULL if allocation failed.
  */
-LWS_VISIBLE LWS_EXTERN lws_dsh_t *
+LWS_VISIBLE LWS_EXTERN struct lws_dsh *
 lws_dsh_create(lws_dll2_owner_t *owner, size_t buffer_size, int count_kinds);
 
 /**
@@ -82,7 +80,7 @@ lws_dsh_create(lws_dll2_owner_t *owner, size_t buffer_size, int count_kinds);
  * unmigratable objects are cleanly destroyed.
  */
 LWS_VISIBLE LWS_EXTERN void
-lws_dsh_destroy(lws_dsh_t **pdsh);
+lws_dsh_destroy(struct lws_dsh **pdsh);
 
 /**
  * lws_dsh_alloc_tail() - make a suballocation inside a dsh
@@ -103,8 +101,8 @@ lws_dsh_destroy(lws_dsh_t **pdsh);
  * The suballocation is added to the kind-specific FIFO at the tail.
  */
 LWS_VISIBLE LWS_EXTERN int
-lws_dsh_alloc_tail(lws_dsh_t *dsh, int kind, const void *src1, size_t size1,
-		    const void *src2, size_t size2);
+lws_dsh_alloc_tail(struct lws_dsh *dsh, int kind, const void *src1,
+		   size_t size1, const void *src2, size_t size2);
 
 /**
  * lws_dsh_free() - free a suballocation from the dsh
@@ -133,7 +131,7 @@ lws_dsh_free(void **obj);
  * free list.
  */
 LWS_VISIBLE LWS_EXTERN int
-lws_dsh_get_head(lws_dsh_t *dsh, int kind, void **obj, size_t *size);
+lws_dsh_get_head(struct lws_dsh *dsh, int kind, void **obj, size_t *size);
 
 /**
  * lws_dsh_describe() - DEBUG BUILDS ONLY dump the dsh to the logs
@@ -144,4 +142,4 @@ lws_dsh_get_head(lws_dsh_t *dsh, int kind, void **obj, size_t *size);
  * Useful information for debugging lws_dsh
  */
 LWS_VISIBLE LWS_EXTERN void
-lws_dsh_describe(lws_dsh_t *dsh, const char *desc);
+lws_dsh_describe(struct lws_dsh *dsh, const char *desc);
diff --git a/include/libwebsockets/lws-sequencer.h b/include/libwebsockets/lws-sequencer.h
index cfe535b17..4b50b824f 100644
--- a/include/libwebsockets/lws-sequencer.h
+++ b/include/libwebsockets/lws-sequencer.h
@@ -57,8 +57,6 @@ typedef enum lws_seq_cb_return {
 	LWSSEQ_RET_DESTROY
 } lws_seq_cb_return_t;
 
-typedef struct lws_sequencer lws_seq_t; /* opaque */
-
 /*
  * handler for this sequencer.  Return 0 if OK else nonzero to destroy the
  * sequencer.  LWSSEQ_DESTROYED will be called back to the handler so it can
@@ -98,7 +96,7 @@ typedef struct lws_seq_info {
  *
  * pt locking is used to protect the related data structures.
  */
-LWS_VISIBLE LWS_EXTERN lws_seq_t *
+LWS_VISIBLE LWS_EXTERN struct lws_sequencer *
 lws_seq_create(lws_seq_info_t *info);
 
 /**
@@ -112,7 +110,7 @@ lws_seq_create(lws_seq_info_t *info);
  * set to NULL.
  */
 LWS_VISIBLE LWS_EXTERN void
-lws_seq_destroy(lws_seq_t **seq);
+lws_seq_destroy(struct lws_sequencer **seq);
 
 /**
  * lws_seq_queue_event() - queue an event on the given sequencer
@@ -132,7 +130,7 @@ lws_seq_destroy(lws_seq_t **seq);
  * values here.
  */
 LWS_VISIBLE LWS_EXTERN int
-lws_seq_queue_event(lws_seq_t *seq, lws_seq_events_t e, void *data,
+lws_seq_queue_event(struct lws_sequencer *seq, lws_seq_events_t e, void *data,
 			  void *aux);
 
 /**
@@ -152,7 +150,7 @@ lws_seq_queue_event(lws_seq_t *seq, lws_seq_events_t e, void *data,
  * close message yet.
  */
 LWS_VISIBLE LWS_EXTERN int
-lws_seq_check_wsi(lws_seq_t *seq, struct lws *wsi);
+lws_seq_check_wsi(struct lws_sequencer *seq, struct lws *wsi);
 
 #define LWSSEQTO_NONE 0
 
@@ -182,7 +180,7 @@ lws_seq_check_wsi(lws_seq_t *seq, struct lws *wsi);
  * react appropriately.
  */
 LWS_VISIBLE LWS_EXTERN int
-lws_seq_timeout_us(lws_seq_t *seq, lws_usec_t us);
+lws_seq_timeout_us(struct lws_sequencer *seq, lws_usec_t us);
 
 /**
  * lws_seq_from_user(): get the lws_seq_t pointer from the user ptr
@@ -197,7 +195,7 @@ lws_seq_timeout_us(lws_seq_t *seq, lws_usec_t us);
  * size of the lws_seq_t is unknown to user code, this helper does it for
  * you.
  */
-LWS_VISIBLE LWS_EXTERN lws_seq_t *
+LWS_VISIBLE LWS_EXTERN struct lws_sequencer *
 lws_seq_from_user(void *u);
 
 /**
@@ -210,7 +208,7 @@ lws_seq_from_user(void *u);
  * step considering a global sequencer lifetime limit.
  */
 LWS_VISIBLE LWS_EXTERN lws_usec_t
-lws_seq_us_since_creation(lws_seq_t *seq);
+lws_seq_us_since_creation(struct lws_sequencer *seq);
 
 /**
  * lws_seq_name(): get the name of this sequencer
@@ -221,7 +219,7 @@ lws_seq_us_since_creation(lws_seq_t *seq);
  * annotate logging when then are multiple sequencers in play.
  */
 LWS_VISIBLE LWS_EXTERN const char *
-lws_seq_name(lws_seq_t *seq);
+lws_seq_name(struct lws_sequencer *seq);
 
 /**
  * lws_seq_get_context(): get the lws_context sequencer was created on
@@ -232,4 +230,4 @@ lws_seq_name(lws_seq_t *seq);
  * pointer handy.
  */
 LWS_VISIBLE LWS_EXTERN struct lws_context *
-lws_seq_get_context(lws_seq_t *seq);
+lws_seq_get_context(struct lws_sequencer *seq);
diff --git a/include/libwebsockets/lws-timeout-timer.h b/include/libwebsockets/lws-timeout-timer.h
index eafef6e54..2253a40e4 100644
--- a/include/libwebsockets/lws-timeout-timer.h
+++ b/include/libwebsockets/lws-timeout-timer.h
@@ -194,9 +194,9 @@ lws_timed_callback_vh_protocol_us(struct lws_vhost *vh,
 				  const struct lws_protocols *prot, int reason,
 				  lws_usec_t us);
 
+struct lws_sorted_usec_list;
 
-typedef struct lws_sorted_usec_list lws_sorted_usec_list_t;
-typedef void (*sul_cb_t)(lws_sorted_usec_list_t *sul);
+typedef void (*sul_cb_t)(struct lws_sorted_usec_list *sul);
 
 typedef struct lws_sorted_usec_list {
 	struct lws_dll2 list;	/* simplify the code by keeping this at start */
diff --git a/lib/core-net/private-lib-core-net.h b/lib/core-net/private-lib-core-net.h
index b25011d66..7d4f86f60 100644
--- a/lib/core-net/private-lib-core-net.h
+++ b/lib/core-net/private-lib-core-net.h
@@ -275,11 +275,9 @@ typedef struct lws_dsh_obj_head {
 	int				kind;
 } lws_dsh_obj_head_t;
 
-typedef struct lws_dsh lws_dsh_t;
-
 typedef struct lws_dsh_obj {
 	lws_dll2_t			list;	/* must be first */
-	lws_dsh_t			*dsh;	/* invalid when on free list */
+	struct lws_dsh			*dsh;	/* invalid when on free list */
 	size_t				size;	/* invalid when on free list */
 	size_t				asize;
 } lws_dsh_obj_t;
@@ -581,7 +579,7 @@ struct lws {
 	const struct lws_protocols *protocol;
 	struct lws_dll2 same_vh_protocol;
 
-	lws_seq_t *seq;	/* associated sequencer if any */
+	struct lws_sequencer *seq;	/* associated sequencer if any */
 
 	struct lws_dll2 dll_buflist; /* guys with pending rxflow */
 
diff --git a/lib/roles/http/private-lib-roles-http.h b/lib/roles/http/private-lib-roles-http.h
index 120e7409d..1e568dd85 100644
--- a/lib/roles/http/private-lib-roles-http.h
+++ b/lib/roles/http/private-lib-roles-http.h
@@ -305,7 +305,5 @@ int
 lws_http_proxy_start(struct lws *wsi, const struct lws_http_mount *hit,
 		     char *uri_ptr, char ws);
 
-typedef struct lws_sorted_usec_list lws_sorted_usec_list_t;
-
 void
 lws_sul_http_ah_lifecheck(lws_sorted_usec_list_t *sul);
diff --git a/minimal-examples/api-tests/api-test-lws_struct-json/CMakeLists.txt b/minimal-examples/api-tests/api-test-lws_struct-json/CMakeLists.txt
index a0900f866..83e37da06 100644
--- a/minimal-examples/api-tests/api-test-lws_struct-json/CMakeLists.txt
+++ b/minimal-examples/api-tests/api-test-lws_struct-json/CMakeLists.txt
@@ -61,7 +61,10 @@ MACRO(require_lws_config reqconfig _val result)
 	endif()
 ENDMACRO()
 
+set(requirements 1)
+require_lws_config(LWS_WITH_STRUCT_JSON 1 requirements)
 
+if (requirements)
 
 	add_executable(${SAMP} ${SRCS})
 
@@ -71,3 +74,4 @@ ENDMACRO()
 	else()
 		target_link_libraries(${SAMP} websockets)
 	endif()
+endif()