The grub2-xcat rpm/deb package can be built from the grub2 source package shipped in Redhat/Fedora/CentOS...

The steps:

1.build grub2-xcat rpm

For rpm package compling, a RHEL 7 environment on powerpc64 is required. Please make sure all the necessary build tools are installed, the list of the build tools can be showed by:
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rpm -qpR <the name of your grub2 source rpm file>
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(1)obtain the grub2 source rpm 
The latest source rpm file of grub2 can be obtained from the source codes of the Red Hat Enterprse Linux. The current source rpm file, grub2-2.02-0.16.ael7b.src.rpm, was obtained from RHEL 7.1. 

(2)update the Makefile
When a new source rpm file is available, please update the following line in the Makefile accordingly. 
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SRC_RPM = <the name of your grub2 source rpm file>
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(3)run "./makerpm" to generate the grub2-xcat rpm, which can be found in current dir.

(4)upload the grub2-xcat rpm to the build server and checkin the modified Makefile to xcat-dep git code base.

2. build grub2-deb rpm  

For deb package generating, a Debian or Ubunutu environment on any architecture wilth alien installed should work. 
running "./makedeb" will convert the grub2-xcat rpm generated above to deb package. 

Finally, upload the deb package to the build server.