patch 9.1.0821: 'findexpr' completion doesn't set v:fname to cmdline argument

Problem:  'findexpr' completion doesn't set v:fname to cmdline argument.
Solution: Set v:fname to the cmdline argument as-is (zeertzjq).

closes: #15934

Signed-off-by: zeertzjq <zeertzjq@outlook.com>
Signed-off-by: Yegappan Lakshmanan <yegappan@yahoo.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/evalvars.c b/src/evalvars.c
index f18b516..9f03ada 100644
--- a/src/evalvars.c
+++ b/src/evalvars.c
@@ -161,6 +161,7 @@
     {VV_NAME("t_typealias",	 VAR_NUMBER), NULL, VV_RO},
     {VV_NAME("t_enum",		 VAR_NUMBER), NULL, VV_RO},
     {VV_NAME("t_enumvalue",	 VAR_NUMBER), NULL, VV_RO},
+    {VV_NAME("cmdcomplete",	 VAR_BOOL), NULL, VV_RO},
 };
 
 // shorthand
@@ -234,6 +235,7 @@
     set_vim_var_nr(VV_SEARCHFORWARD, 1L);
     set_vim_var_nr(VV_HLSEARCH, 1L);
     set_vim_var_nr(VV_EXITING, VVAL_NULL);
+    set_vim_var_nr(VV_CMDCOMPLETE, VVAL_FALSE);
     set_vim_var_dict(VV_COMPLETED_ITEM, dict_alloc_lock(VAR_FIXED));
     set_vim_var_list(VV_ERRORS, list_alloc());
     set_vim_var_dict(VV_EVENT, dict_alloc_lock(VAR_FIXED));