Adds scripts to build RPMs for XRootD with SSI support

xrootd.spec.in in the XRootD SSI branch does not package the SSI
libraries/headers. I'm putting a patched version here temporarily until
Michal or Andy can fix it in the main XRootD repository.

xroot_rpms/Dockerfile

+# ******************************************************************************
+#
+# The CERN Tape Archive (CTA) project
+# Copyright (C) 2017  CERN
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+# ****************************************************************************/
+
+# Docker image to build XRootD RPMs
+
+# FROM must be the first command in Dockerfile
+
+FROM gitlab-registry.cern.ch/linuxsupport/cc7-base
+
+# Set up default environment
+
+RUN yum clean all && \
+    yum update -y && \
+    yum install -y \
+      ccache \
+      cgdb \
+      cmake \
+      gcc-c++ \
+      gdb \
+      git \
+      ltrace \
+      make \
+      psmisc \
+      rpm-build \
+      strace \
+      sudo \
+      vim \
+      yum-utils
+
+# Get XRootD
+
+RUN git clone https://github.com/xrootd/xrootd.git
+
+# Check out SSIV2
+
+RUN cd xrootd && git checkout xrdssiV2
+
+# Copy in patched xrootd.spec.in
+
+ADD xrootd.spec.in /xrootd/packaging/rhel/xrootd.spec.in
+RUN cp xrootd/packaging/rhel/xrootd.spec.in xrootd.spec
+
+# Install all necessary build dependencies
+
+RUN yum-builddep -y xrootd.spec
+
+# Create XRootD source RPM
+
+RUN cd xrootd/packaging && ./makesrpm.sh
+
+# Create final RPMs from the source RPM
+
+RUN rpmbuild --define "_topdir ${PWD}/rpmbuild_xrootd" --rebuild xrootd/packaging/*.src.rpm
+
+# Notes on XRootD version
+#
+# Newer version of CTA requires xroot >= 4.4.1-1
+#
+# epel version is more recent but eos-citrine-depend repo has a higher priority (4) than epel,
+#   so: need to set epel priority to 4:
+#
+#       RUN yum-config-manager --enable epel --setopt="epel.priority=4" 
+#
+#   or: if taking the older version from eos, eos-citrine-depend must be enabled so that the older version of xroot is
+#       installed by cta-cli and is not conflicting later when installing eos...

xroot_rpms/README.md

+# Build XRootD RPMs
+
+The version of xrootd.spec.in in the xrootd xrdssiV2 branch does not package the SSI library and header files.
+
+This is the temporary home for the patched version of xrootd.spec.in, until Michal or Andy can integrate it
+properly into the xrootd git respository.
+
+To build the RPMs:
+```
+./build-rpms
+```
+

xroot_rpms/build-rpms

+#!/bin/sh
+
+sudo docker build . -f ./Dockerfile -t buildxroot
+
+id=$(sudo docker create buildxroot bash)
+
+sudo docker cp ${id}:rpmbuild_xrootd/RPMS/x86_64/ .
+
+sudo docker rm -v ${id}