Scope

Add a default VERSION_CURRENT file to the source to ease building when git history is unavailable. Update the release process to handle updating the VERSION_CURRENT file.

Consider simplifying the behavior for obtaining the version.

Background & Motivation

Similar to CDRIVER-4809, this may ease building from source when no git history is available. This may help prevent the possibility of building a tarball without a VERSION_CURRENT file (as happened in the 3.9.0 release).

The version is currently obtained from these sources in order of preference:

• The CMake option BUILD_VERSION if set
• Then the ${CMAKE_BINARY_DIR}/VERSION_CURRENT if present
• Then the build/VERSION_CURRENT if present
• Then the version is calculated with calc_release_version.py and written to ${CMAKE_BINARY_DIR}/VERSION_CURRENT

If a VERSION_CURRENT file is included in build/VERSION_CURRENT, this may permit simplifying the behavior to:

• The CMake option BUILD_VERSION if set
• Otherwise the build/VERSION_CURRENT file