ci: use GitLab CI to build

Added a GitLab CI config which has a lot more flexibility to allow us to
test a lot more distro configurations than Travis can and even build
test on FreeBSD. This includes a modified copy of scripts/travis-build
that is expected to diverge future over time as we build more than what
Travis is currently building.

Signed-off-by: Doug Goldstein <cardoe@cardoe.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>

automation/scripts/build

@@ -0,0 +1,31 @@
+#!/bin/bash -ex
+
+$CC --version
+
+# random config or default config
+if [[ "${RANDCONFIG}" == "y" ]]; then
+    make -C xen KCONFIG_ALLCONFIG=tools/kconfig/allrandom.config randconfig
+else
+    make -C xen defconfig
+fi
+
+# build up our configure options
+cfgargs=()
+cfgargs+=("--disable-stubdom") # more work needed into building this
+cfgargs+=("--disable-rombios")
+cfgargs+=("--enable-docs")
+
+# SeaBIOS cannot be built with clang
+if [[ "${CC}" == "clang" ]]; then
+    cfgargs+=("--with-system-seabios=/usr/share/seabios/bios.bin")
+fi
+
+if [[ "${XEN_TARGET_ARCH}" == "x86_64" ]]; then
+    cfgargs+=("--enable-tools")
+else
+    cfgargs+=("--disable-tools") # we don't have the cross depends installed
+fi
+
+./configure "${cfgargs[@]}"
+
+make dist