diff --git a/include/mimalloc/internal.h b/include/mimalloc/internal.h
index a76f7baf..c9f69a26 100644
--- a/include/mimalloc/internal.h
+++ b/include/mimalloc/internal.h
@@ -127,6 +127,7 @@ mi_threadid_t _mi_thread_id(void) mi_attr_noexcept;
 size_t        _mi_thread_seq_id(void) mi_attr_noexcept;
 mi_tld_t*     _mi_thread_tld(void) mi_attr_noexcept;
 void          _mi_heap_guarded_init(mi_heap_t* heap);
+mi_heap_t*    _mi_heap_main_get(void);
 
 // os.c
 void          _mi_os_init(void);                                            // called from process init
diff --git a/src/init.c b/src/init.c
index 870e5ea4..3e65e811 100644
--- a/src/init.c
+++ b/src/init.c
@@ -138,7 +138,7 @@ mi_decl_cache_align const mi_heap_t _mi_heap_empty = {
   MI_MEMID_STATIC
 };
 
-extern mi_heap_t heap_main;
+static mi_decl_cache_align mi_heap_t heap_main;
 
 static mi_decl_cache_align mi_tld_t tld_main = {
   0,                      // thread_id
@@ -153,7 +153,7 @@ static mi_decl_cache_align mi_tld_t tld_main = {
   MI_MEMID_STATIC         // memid
 };
 
-mi_decl_cache_align mi_heap_t heap_main = {
+static mi_decl_cache_align mi_heap_t heap_main = {
   &tld_main,              // thread local data
   NULL,                   // exclusive arena
   0,                      // initial cookie
@@ -266,7 +266,7 @@ static void mi_heap_main_init(void) {
   }
 }
 
-mi_heap_t* heap_main_get(void) {
+mi_heap_t* _mi_heap_main_get(void) {
   mi_heap_main_init();
   return &heap_main;
 }