My auto-designation macro has been superseded by joelpt's Quickfort. See the linked forum thread for details.
Dwarf Companion Exe Version
I maintain an exe version of Dwarf Companion with no dependencies. The most current download link is on that page in the "Self-packaged executables" section.
This is a macro to aid with rewalling. To use, copy-paste the script into a new .ahk file and run the script with AutoHotKey. Then, in Dwarf Fortress, press b-C-w, move the cursor to where you want to start the wall, and hold Ctrl-Shift-Arrowkey, using the direction you want to rewall in. To build floors, press b-C-f instead, and use Ctrl-Alt-Arrowkey. To stop, just release the keys.
The script will use the first material in the list. I suggest you create a stockpile near the construction site that only accepts the item you wish to build with and temporarily forbid any nearby materials you don't want to build with.