Fix SYSTEMC_UNITY_BUILD for static builds with custom main()

When building SystemC as a static library with SYSTEMC_UNITY_BUILD=ON,
linking fails if the user defines their own main() (e.g., in a test)
because the internal sc_main.cpp object is included in the unity build
and conflicts with the custom main().

This patch excludes sc_main.cpp from unity builds to restore expected
behavior for static linking scenarios with external main() definitions.

Signed-off-by: Ruben Brandhofer <[email protected]>

Author: RubBra

src/CMakeLists.txt

@@ -129,6 +129,7 @@ function(add_systemc_library libName scBuildDefine)
     if(SYSTEMC_UNITY_BUILD)
       message(STATUS "Enable SystemC unity build")
       set_target_properties(${libName} PROPERTIES UNITY_BUILD ON)
+      set_source_files_properties(sysc/kernel/sc_main.cpp PROPERTIES SKIP_UNITY_BUILD_INCLUSION ON)
       set_source_files_properties(sysc/utils/sc_utils_ids.cpp PROPERTIES SKIP_UNITY_BUILD_INCLUSION ON)
     else()
       message(STATUS "Disable SystemC unity build")