ANT build basedir not evaluated on version 1.8.1

Question

I have a prefectly working build.xml file on ant 1.8.0 When I've tried to upgrade ant to 1.8.1 ant it stopped working.

I get an error where I use the ${basedir} variable because these variable is not evaluated.

This is the output

Project base dir set to: D:\project

Then I use this variable to set other variables like

build.dir=${basedir}/build

but when I execute the target I get that build.dir value is ${basedir}/build instead of D:\project/build

Any ideas? thanks!