[cmake] Symbol OGS_USE_PYTHON can be private.

ProcessLib/BoundaryConditionAndSourceTerm/Python/CMakeLists.txt

@@ -16,14 +16,15 @@ ogs_add_library(
 
 target_compile_definitions(
     ProcessLibBoundaryConditionAndSourceTermPython
-    PUBLIC OGS_USE_PYTHON
-           # Enabled elements
+    PUBLIC # Enabled elements
            OGS_MAX_ELEMENT_DIM=${OGS_MAX_ELEMENT_DIM}
            OGS_MAX_ELEMENT_ORDER=${OGS_MAX_ELEMENT_ORDER}
            $<$<BOOL:${OGS_ENABLE_ELEMENT_SIMPLEX}>:OGS_ENABLE_ELEMENT_SIMPLEX>
            $<$<BOOL:${OGS_ENABLE_ELEMENT_CUBOID}>:OGS_ENABLE_ELEMENT_CUBOID>
            $<$<BOOL:${OGS_ENABLE_ELEMENT_PRISM}>:OGS_ENABLE_ELEMENT_PRISM>
            $<$<BOOL:${OGS_ENABLE_ELEMENT_PYRAMID}>:OGS_ENABLE_ELEMENT_PYRAMID>
+    PRIVATE
+        OGS_USE_PYTHON
 )
 
 target_link_libraries(