DOCSP-49002 Auto-downloaded C Driver incorrectly inherits BUILD_VERSION (#124)

* DOCSP-49002 Auto-downloaded C Driver incorrectly inherits BUILD_VERSION

* edit

* edit

* MW review

* tech review

* vale check

* remove build version mention

* edit

Author: lindseymoore

source/whats-new.txt

@@ -42,6 +42,20 @@ The v4.0 driver release includes the following new features:
 - Adds a getter method for the ``start_at_operation_time`` field of a 
   ``mongocxx::options::change_stream`` instance.
 
+The release includes the following bug:
+
+- CMake might incorrectly set the API version for an 
+  auto-downloaded C driver to ``0.0.0`` when the CMake project is configured 
+  more than once or to the same value as the C++ driver's 
+  API version when ``BUILD_VERSION`` is explicitly set during initial configuration. 
+  CMake will only auto-download the C driver with the C++ driver 
+  if it cannot find an existing C driver installation by using ``find_package()``. 
+  This bug will be fixed in an upcoming patch release. 
+
+To learn more about this release, see the
+`v4.0 Release Notes <https://github.com/mongodb/mongo-cxx-driver/releases/tag/r4.0.0>`__
+on GitHub.
+
 .. _version-3.11:
 
 What's New in 3.11
@@ -61,6 +75,16 @@ The v3.11 driver release includes the following new features:
   Encryption </core/queryable-encryption>` in the {+mdb-server+} manual.
 - Adds ``empty()`` member function for ``mongocxx::v_noabi::bulk_write``.
 
+The release includes the following bug:
+
+- CMake might incorrectly set the API version for an 
+  auto-downloaded C driver to ``0.0.0`` when the CMake project is configured 
+  more than once or to the same value as the C++ driver's 
+  API version when ``BUILD_VERSION`` is explicitly set during initial configuration. 
+  CMake will only auto-download the C driver with the C++ driver 
+  if it cannot find an existing C driver installation by using ``find_package()``. 
+  This bug will be fixed in an upcoming patch release. 
+
 To learn more about this release, see the
 `v3.11 Release Notes <https://github.com/mongodb/mongo-cxx-driver/releases/tag/r3.11.0>`__
 on GitHub.