support/dependencies/dependencies.sh: ensure git is >= 2.0.0 for vendoring

The go vendoring fails on CentOS 7 (which uses git 1.8.3.1) with errors
related to shallow clones:

make docker-compose-source
..
go: downloading github.com/matttproud/golang_protobuf_extensions v1.0.4
github.com/docker/compose/v2/pkg/mocks imports
        github.com/theupdateframework/notary/client imports
        github.com/docker/go/canonical/json: github.com/docker/go@v1.5.1-1.0.20160303222718-d30aec9fd63c: invalid pseudo-version: git fetch --unshallow -f origin in /home/jacmet/source/buildroot-mirror/output/host/share/go-path/pkg/mod/cache/vcs/48fbd2dfabec81f4c93170677bfc89087d4bec07a2d08f6ca5ce3d17962677ee: exit status 128:
        fatal: git fetch-pack: expected shallow list
make[1]: *** [/home/jacmet/source/buildroot-mirror/output/build/docker-compose-2.15.1/.stamp_downloaded] Error 1

It works with git 2.0.0 (released May 2014, included in Debian 8), so check
for >= 2.0.0 with logic similar to the GNU patch version check.

Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
(cherry picked from commit f229564c36ec64c1f1292b7281ae0bd33840d7a4)
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

support/dependencies/dependencies.sh

@@ -183,6 +183,16 @@ for prog in perl tar wget cpio unzip rsync bc cmp find xargs ${DL_TOOLS} ; do
 			echo "  xargs is usually part of the findutils package in your distribution"
 		fi
 	fi
+
+	# we need git >= 2.0.0 for shallow clones / vendoring
+	if test $prog = "git" ; then
+		GIT_VERSION="$(git --version | sed -n 's/^git version \(.*\)/\1/p')"
+		GIT_MAJOR="$(echo "${GIT_VERSION}" | cut -d . -f 1)"
+		if [ "${GIT_MAJOR}" -lt 2 ]; then
+			echo "You have git '${GIT_VERSION}' installed. Git >= 2.0.0 is required"
+			exit 1
+		fi
+	fi
 done
 
 if test "${missing_progs}" = "yes" ; then