fix(make): work around localvar_inherit

Author: akinomyoga

completions/make

@@ -110,7 +110,7 @@ _comp_cmd_make()
     elif [[ $cur == *=* ]]; then
         prev=${cur%%=*}
         cur=${cur#*=}
-        local diropt
+        local diropt=""
         [[ ${prev,,} == *dir?(ectory) ]] && diropt=-d
         _comp_compgen_filedir $diropt
     else