ntdll: Add WINE_DISABLE_WRITE_WATCH env var to disable write watch support.

Massively improves performance for corert games (Streets of Rage 4).
Could be fixed properly with Linux kernel changes.

Author: Paul Gofman

dlls/ntdll/unix/virtual.c

@@ -4523,6 +4523,22 @@ static NTSTATUS allocate_virtual_memory( void **ret, SIZE_T *size_ptr, ULONG typ
     SIZE_T size = *size_ptr;
     NTSTATUS status = STATUS_SUCCESS;
 
+    if (type & MEM_WRITE_WATCH)
+    {
+        static int disable = -1;
+
+        if (disable == -1)
+        {
+            const char *env_var;
+
+            if ((disable = (env_var = getenv("WINE_DISABLE_WRITE_WATCH")) && atoi(env_var)))
+                FIXME("Disabling write watch support.\n");
+        }
+
+        if (disable)
+            return STATUS_NOT_SUPPORTED;
+    }
+
     /* Round parameters to a page boundary */
 
     if (is_beyond_limit( 0, size, working_set_limit )) return STATUS_WORKING_SET_LIMIT_RANGE;