patch 9.0.1381: ACCESS_ names have a conflict with on some systems

Problem:    ACCESS_ names have a conflict with on some systems.
Solution:   Rename by prepending VIM_. (Ola Söder, closes #12105)
diff --git a/src/vim9class.c b/src/vim9class.c
index a2b186e..74664f1 100644
--- a/src/vim9class.c
+++ b/src/vim9class.c
@@ -148,8 +148,8 @@
 	return FAIL;
     ocmember_T *m = ((ocmember_T *)gap->ga_data) + gap->ga_len;
     m->ocm_name = vim_strnsave(varname, varname_end - varname);
-    m->ocm_access = has_public ? ACCESS_ALL
-			      : *varname == '_' ? ACCESS_PRIVATE : ACCESS_READ;
+    m->ocm_access = has_public ? VIM_ACCESS_ALL
+		      : *varname == '_' ? VIM_ACCESS_PRIVATE : VIM_ACCESS_READ;
     m->ocm_type = type;
     if (init_expr != NULL)
 	m->ocm_init = init_expr;