Fix cmake build of programs

Signed-off-by: Manuel Pégourié-Gonnard <manuel.pegourie-gonnard@arm.com>
diff --git a/programs/util/CMakeLists.txt b/programs/util/CMakeLists.txt
index 2a11212..7fc58cb 100644
--- a/programs/util/CMakeLists.txt
+++ b/programs/util/CMakeLists.txt
@@ -10,6 +10,7 @@
 foreach(exe IN LISTS executables)
     add_executable(${exe} ${exe}.c $<TARGET_OBJECTS:mbedtls_test>)
     target_link_libraries(${exe} ${libs})
+    target_include_directories(${exe} PRIVATE ${CMAKE_CURRENT_SOURCE_DIR}/../../tests/include)
 endforeach()
 
 install(TARGETS ${executables}