PROJECT_BINARY_DIR
From Get docs
Cmake/docs/3.21/variable/project binary dir
PROJECT_BINARY_DIR
Full path to build directory for project.
This is the binary directory of the most recent project() command.
© 2000–2021 Kitware, Inc. and Contributors
Licensed under the BSD 3-clause License.
https://cmake.org/cmake/help/v3.21/variable/PROJECT_BINARY_DIR.html