fix(make): work around custom IFS

Author: akinomyoga

completions/make

@@ -112,7 +112,7 @@ _comp_cmd_make()
         cur=${cur#*=}
         local diropt=""
         [[ ${prev,,} == *dir?(ectory) ]] && diropt=-d
-        _comp_compgen_filedir $diropt
+        _comp_compgen_filedir ${diropt:+"$diropt"}
     else
         # before we check for makefiles, see if a path was specified
         # with -C/--directory