[ITK-users] cmake error when configuring ITK with the variational registration module

[asertyuio]

Hi all,

Each time I include the variational registration module, I get the
following error while configuring with ccmake :

```
# Insight Journal Handle: https://hdl.handle.net/10380/3460
# Contact: Alexander Schmidt-Richberg <a.schmidt-richberg at imperial.ac.uk>
#          Jan Ehrhardt <ehrhardt at imi.uni-luebeck.de>
#          Rene Werner <r.werner at uke.de>
itk_fetch_module(VariationalRegistration
  "A module to perform variational image registration.
https://hdl.handle.net/10380/3460"
  GIT_REPOSITORY
${git_protocol}://github.com/InsightSoftwareConsortium/ITKVariationalRegistration.git
  GIT_TAG 5110f1b4304f450b46bbbaf0f3818a4bac65b154
)
```

I'm using the master branch in git as a version of ITK.

Seems like a bug... Any idea ?
Yann