Bug description

When using a clean Windows box to but the am-external, this will block forever in yarn
with

[ERROR] warning Waiting for the other yarn instance to finish (pid undefined, inside undefined)

How to reproduce the issue

Get a fresh clean Windows box

1. On a Windows box without c:\tmp or even on mounted directory where there is no <drive>:\tmp
2. cd openam-ui ; mvn clean package

Expected behaviour

Builds

Current behaviour

Hangs at Yarn

Work around

a) Run yarn without --mutex=
b) (or mkdir c:\tmp)
c) Or run in Windows "bash" where there is probably some /tmp exists

Or edit the pom.xml from using /tmp to ${java.io.tmpdir}

Code analysis

The mvn code works only on Unix and not on windows
Maybe an instruction given to update the pom.xml to set and
temp directory or mkdir c:\tmp

Change the pom.xml for openam-ui-ria/pom.xml that is /tmp with  ${java.io.tmpdir}