cgmemmgr,macos: add missing shared_map_lock initialization

(cherry picked from commit 3661a08)

src/cgmemmgr.cpp

@@ -212,7 +212,12 @@ static size_t map_offset = 0;
 // Hopefully no one will set a ulimit for this to be a problem...
 static constexpr size_t map_size_inc_default = 128 * 1024 * 1024;
 static size_t map_size = 0;
-static jl_mutex_t shared_map_lock;
+static struct _make_shared_map_lock {
+    uv_mutex_t mtx;
+    _make_shared_map_lock() {
+        uv_mutex_init(&mtx);
+    };
+} shared_map_lock;
 
 static size_t get_map_size_inc()
 {
@@ -258,7 +263,7 @@ static void *alloc_shared_page(size_t size, size_t *id, bool exec)
     *id = off;
     size_t map_size_inc = get_map_size_inc();
     if (__unlikely(off + size > map_size)) {
-        JL_LOCK_NOGC(&shared_map_lock);
+        uv_mutex_lock(&shared_map_lock.mtx);
         size_t old_size = map_size;
         while (off + size > map_size)
             map_size += map_size_inc;
@@ -269,7 +274,7 @@ static void *alloc_shared_page(size_t size, size_t *id, bool exec)
                 abort();
             }
         }
-        JL_UNLOCK_NOGC(&shared_map_lock);
+        uv_mutex_unlock(&shared_map_lock.mtx);
     }
     return create_shared_map(size, off);
 }