CMake: Make benchmarks buildable standalone


Add the necessary project file stanza that allows to configure the
benchmarks with qt-cmake-private.

Change-Id: Iaae82c1eb274c9a9ff3074c6a5f7ba5d15cbd1b1
Reviewed-by: Alexandru Croitor <alexandru.croitor@qt.io>
commitf2c9b9a0db911c59bc1a93f43175bdacd767d9bd
parentfd7030e6f8a7dee67cab4761bdac7cfe964820dd
authorJoerg Bornemann <joerg.bornemann@qt.io>
committerJoerg Bornemann <joerg.bornemann@qt.io>
commit timeWed, 30 Sep 2026 13:33:45 +0000