C:\>perl -CiO -i.bak -pe "INIT { @ARGV = <@ARGV> } s{^\s*<(?:Out|Int)Dir>.+?[/\\]ReleaseDLL\K}{32}" */*.vcxproj

C:\>diff Temp\fred.vcxproj.bak Temp\fred.vcxproj
9,10c9,10
<     <OutDir>.\../../products/bin/ReleaseDLL\</OutDir>
<     <IntDir>.\ReleaseDLL\</IntDir>
---
>     <OutDir>.\../../products/bin/ReleaseDLL32\</OutDir>
>     <IntDir>.\ReleaseDLL32\</IntDir>
15,16c15,16
<     <OutDir>.\../../products/bin/ReleaseDLL\</OutDir>
<     <IntDir>.\ReleaseDLL\</IntDir>
---
>     <OutDir>.\../../products/bin/ReleaseDLL32\</OutDir>
>     <IntDir>.\ReleaseDLL32\</IntDir>

C:\>