Made the test build against the build directory set CMAKE_PREFIX_PATH…

… correctly.

So that headers/libraries in the build directory could be found
correctly.

test/CMakeLists.txt

@@ -1,4 +1,4 @@
-# Copyright (C) 1995-2019, Rene Brun and Fons Rademakers.
+# Copyright (C) 1995-2022, Rene Brun and Fons Rademakers.
 # All rights reserved.
 #
 # For the licensing terms see $ROOTSYS/LICENSE.
@@ -449,13 +449,15 @@ if (NOT cxxmodules)
  ROOT_ADD_TEST(test-periodic-build
  COMMAND ${CMAKE_CTEST_COMMAND} ${build_generator_args}
  --build-and-test ${CMAKE_CURRENT_SOURCE_DIR}/periodic periodic-build
+ --build-options -DCMAKE_PREFIX_PATH=${CMAKE_BINARY_DIR}
  )
  else()
  ROOT_ADD_TEST(test-periodic-build
  COMMAND
  env CC=${CMAKE_C_COMPILER} CXX=${CMAKE_CXX_COMPILER}
  ${CMAKE_CTEST_COMMAND} --build-generator ${CMAKE_GENERATOR}
  --build-and-test ${CMAKE_CURRENT_SOURCE_DIR}/periodic periodic-build
+ --build-options -DCMAKE_PREFIX_PATH=${CMAKE_BINARY_DIR}
  )
  endif()
 endif()