Unshallow Mesa history for apt versioning

scripts/build-mesa-opt.sh

@@ -69,6 +69,14 @@ export LD_LIBRARY_PATH="${PREREQ_DIR}${INSTALL_PREFIX}/lib/x86_64-linux-gnu:${PR
 
 git clone --depth 1 --branch "${UPSTREAM_REF}" "${UPSTREAM_GIT_URL}" "${SRC_DIR}"
 
+# The apt version and release notes need more than a shallow HEAD. Expand the
+# clone so commit counts and previous-release comparisons are monotonic.
+if [[ "$(git -C "${SRC_DIR}" rev-parse --is-shallow-repository)" == "true" ]]; then
+  git -C "${SRC_DIR}" fetch --unshallow --tags
+else
+  git -C "${SRC_DIR}" fetch --tags
+fi
+
 detect_upstream_version() {
   local source_dir="${1}"