diff --git a/include/curl/curl.h b/include/curl/curl.h
index 516ede6ae..7fd6d1fa1 100644
--- a/include/curl/curl.h
+++ b/include/curl/curl.h
@@ -91,7 +91,13 @@
 extern "C" {
 #endif
 
+#if defined(BUILDING_LIBCURL) || defined(CURL_STRICTER)
 typedef struct Curl_easy CURL;
+typedef struct Curl_share CURLSH;
+#else
+typedef void CURL;
+typedef void CURLSH;
+#endif
 
 /*
  * libcurl external API function linkage decorations.
@@ -2258,7 +2264,6 @@ typedef void (*curl_unlock_function)(CURL *handle,
                                      curl_lock_data data,
                                      void *userptr);
 
-typedef struct Curl_share CURLSH;
 
 typedef enum {
   CURLSHE_OK,  /* all is fine */
diff --git a/include/curl/multi.h b/include/curl/multi.h
index 7a1040f46..d1e00cc5d 100644
--- a/include/curl/multi.h
+++ b/include/curl/multi.h
@@ -52,7 +52,11 @@
 extern "C" {
 #endif
 
+#if defined(BUILDING_LIBCURL) || defined(CURL_STRICTER)
 typedef struct Curl_multi CURLM;
+#else
+typedef void CURLM;
+#endif
 
 typedef enum {
   CURLM_CALL_MULTI_PERFORM = -1, /* please call curl_multi_perform() or