Fix CMake linking order for dlopen/dlsym symbols

Move CMAKE_DL_LIBS (-ldl) after the static libraries (sems_core,
sems_sip) in the link command. With --whole-archive, the GNU linker
processes libraries in order and needs to see the libraries that
define symbols after the objects that reference them.

This fixes the Debian 11 build failure where linking failed with
undefined references to dlopen, dlclose, dlsym, and dlerror from
libsems_core.a.

Author: marcel

core/CMakeLists.txt

@@ -34,22 +34,22 @@ foreach(EXE_TARGET sems sems_tests)
   if(APPLE)
     target_link_libraries(
       ${EXE_TARGET}
-      ${CMAKE_DL_LIBS}
       -Wl,-force_load
       sems_core
       -Wl,-force_load
       sems_sip
+      ${CMAKE_DL_LIBS}
       event
       event_pthreads
       -rdynamic)
   else()
     target_link_libraries(
       ${EXE_TARGET}
-      ${CMAKE_DL_LIBS}
       -Wl,--whole-archive
       sems_core
       sems_sip
       -Wl,--no-whole-archive
+      ${CMAKE_DL_LIBS}
       event
       event_pthreads
       -rdynamic)