diff --git a/unittest/c-library/CMakeLists.txt b/unittest/c-library/CMakeLists.txt
index 5b5dd4f357..240da8bcf3 100644
--- a/unittest/c-library/CMakeLists.txt
+++ b/unittest/c-library/CMakeLists.txt
@@ -31,28 +31,28 @@ target_compile_definitions(test_library_scatter_gather PRIVATE -DTEST_INPUT_FOLD
 add_test(NAME LibraryScatterGather COMMAND test_library_scatter_gather)
 set_tests_properties(LibraryScatterGather PROPERTIES ENVIRONMENT "LAMMPS_POTENTIALS=${LAMMPS_POTENTIALS_DIR}")
 
-set(TEST_CONFIG_DEFS "-DTEST_INPUT_FOLDER=${CMAKE_CURRENT_SOURCE_DIR};-DLAMMPS_${LAMMPS_SIZES}")
+set(TEST_CONFIG_DEFS "TEST_INPUT_FOLDER=${CMAKE_CURRENT_SOURCE_DIR};LAMMPS_${LAMMPS_SIZES}")
 set(PKG_COUNT 0)
 foreach(PKG ${STANDARD_PACKAGES} ${EXTRA_PACKAGES} ${SUFFIX_PACKAGES})
   if(PKG_${PKG})
     MATH(EXPR PKG_COUNT "${PKG_COUNT}+1")
   endif()
 endforeach()
-list(APPEND TEST_CONFIG_DEFS -DNUM_LAMMPS_PACKAGES=${PKG_COUNT})
+list(APPEND TEST_CONFIG_DEFS NUM_LAMMPS_PACKAGES=${PKG_COUNT})
 
 if(PKG_MANYBODY)
   set(HAS_MANYBODY 1)
 else()
   set(HAS_MANYBODY 0)
 endif()
-list(APPEND TEST_CONFIG_DEFS -DLAMMPS_HAS_MANYBODY=${HAS_MANYBODY})
+list(APPEND TEST_CONFIG_DEFS LAMMPS_HAS_MANYBODY=${HAS_MANYBODY})
 
 if(BUILD_MPI)
   set(HAS_MPI 1)
 else()
   set(HAS_MPI 0)
 endif()
-list(APPEND TEST_CONFIG_DEFS -DLAMMPS_HAS_MPI=${HAS_MPI})
+list(APPEND TEST_CONFIG_DEFS LAMMPS_HAS_MPI=${HAS_MPI})
 
 foreach(WITH "JPEG" "PNG" "GZIP" "FFMPEG")
   if(WITH_${WITH})
@@ -60,7 +60,7 @@ foreach(WITH "JPEG" "PNG" "GZIP" "FFMPEG")
   else()
     set(HAS_${WITH} 0)
   endif()
-  list(APPEND TEST_CONFIG_DEFS -DLAMMPS_HAS_${WITH}=${HAS_${WITH}})
+  list(APPEND TEST_CONFIG_DEFS LAMMPS_HAS_${WITH}=${HAS_${WITH}})
 endforeach()
 
 add_executable(test_library_config test_library_config.cpp test_main.cpp)