In our build-script (build.rs), we won't set the environment variable
'BUILD_VERSION' when the 'git describe' command failed (e.g. when the
current source tree does not contain git information). This patch added
a fall back path where the default value of 'BUILD_VERSION' is based on
the 'cloud-hypervisor' crate version.
Fixes: #1669
Signed-off-by: Bo Chen <chen.bo@intel.com>
Add a build-script to propagate the git commit hash to other crates at
compile time through environment variables, and display the hash along
with the '--version' option.
Fixes#729
Signed-off-by: Bo Chen <chen.bo@intel.com>
