added clean in cpp runtime make files

git-svn-id: https://openmodelica.org/svn/OpenModelica/trunk@18814 f25d12d1-65f4-0310-ae8a-bbce733d8d8e

Author: niklwors

SimulationRuntime/cpp/Makefile

@@ -8,7 +8,7 @@ builddir_bin=$(top_builddir)/build/bin
 builddir_lib=$(top_builddir)/build/lib/omc
 builddir_inc=$(top_builddir)/build/include/omc
 
-runtimeCpp:
+runtimeCpp: clean
 	cd ./Build && echo "change to Build" &&	cmake -D CMAKE_INSTALL_PREFIX:PATH="$(builddir_build)"  ../
 	$(MAKE) -C Build