See variable CMAKE_<CONFIG>_POSTFIX.
This variable is a special case of the more-general CMAKE_<CONFIG>_POSTFIX variable for the DEBUG configuration.
© 2000–2016 Kitware, Inc.
© 2000–2011 Insight Software Consortium
Licensed under the BSD 3-clause License.
https://cmake.org/cmake/help/v3.7/variable/CMAKE_DEBUG_POSTFIX.html