CMake: Add Threads::Threads as public dependency to clangrefactoringbackend library

Change-Id: If7d3d4a7226f034d0e4c66726d3a7beed3480efe
Reviewed-by: Cristian Adam <cristian.adam@qt.io>
Reviewed-by: Eike Ziller <eike.ziller@qt.io>

CMakeLists.txt

@@ -54,6 +54,8 @@ find_package(Qt5
   REQUIRED
 )
 
+find_package(Threads)
+
 # Get information on directories from qmake
 # as this is not yet exported by cmake.
 function(qt5_query_qmake)

src/tools/clangrefactoringbackend/source/CMakeLists.txt

@@ -1,4 +1,5 @@
 add_qtc_library(clangrefactoringbackend_lib STATIC
+  PUBLIC_DEPENDS Threads::Threads
   DEPENDS libclang clangTooling clangIndex clangQuery ClangSupport
   DEFINES CLANGSUPPORT_BUILD_LIB
   PUBLIC_INCLUDES