Require that LIB_VERSION be set as make variable

Since this package is built / released as part of the NVIDIA
Container Toolkit, bumping the version in this repository causes
unnecessary churn. This change REQUIRES that the LIB_VERSION be
set as a make variable or in CI.

Signed-off-by: Evan Lezar <elezar@nvidia.com>

.gitlab-ci.yml

@@ -5,10 +5,12 @@ stages:
   - build-all
 
 variables:
-  # We specify the TOOLKIT_VERSION and TOOLKIT_TAG variable to allow packages
+  # We specify the LIB_VERSION, TOOLKIT_VERSION, and TOOLKIT_TAG variable to allow packages
   # to be built.
+  LIB_VERSION: 999.999.999
+  LIB_TAG: dummy+lib
   TOOLKIT_VERSION: 999.999.999
-  TOOLKIT_TAG: dummy
+  TOOLKIT_TAG: dummy+toolkit
 
 .build-setup: &build-setup
   image: docker:19.03.8

Makefile

@@ -13,8 +13,15 @@
 # limitations under the License.
 
 LIB_NAME := nvidia-docker2
-LIB_VERSION := 2.8.0
-LIB_TAG ?= rc.1
+# Define the package version and tag. Since this package is released as part of
+# the NVIDIA Container Toolkit, these versions are specified where they are
+# built or when invoking the MAKE command.
+LIB_VERSION ?= # Set by CI
+LIB_TAG ?= # Set by CI
+
+ifeq ($(strip $(LIB_VERSION)),)
+$(error LIB_VERSION must be specified)
+endif
 
 # Define the nvidia-container-toolkit version on which the nvidia-docker2
 # package depends. It is recommended that the TOOLKIT_TAG and the LIB_TAG match.