refactor(gdb): use _comp_compgen

Author: akinomyoga

completions/gdb

@@ -19,8 +19,8 @@ _comp_cmd_gdb()
         compopt -o filenames
         if _comp_looks_like_path "$cur"; then
             # compgen -c works as expected if $cur contains any slashes.
-            IFS=$'\n'
-            COMPREPLY=($(PATH="$PATH:." compgen -d -c -- "$cur"))
+            local PATH="$PATH:."
+            _comp_compgen -- -d -c
         else
             # otherwise compgen -c contains Bash's built-in commands,
             # functions and aliases. Thus we need to retrieve the program