To use the compilers in this environment, set the following environment variables:

export TARGETROOT=/opt/xdk-ia64
export SDKROOT=/opt/xdk-ia64

And set your path as needed to access these files. For example:

export PATH=/opt/xdk-ia64/opt/ansic/bin:$PATH
export PATH=/opt/xdk-ia64/opt/fortran90/bin:$PATH
export PATH=/opt/xdk-ia64/opt/aCC/bin:$PATH

These settings will work interactively.  Additional, similar changes would be needed for any automation to use the tools in this extended path location.