Fix OpenMP library usage that has a dependency to pthread that break …

…conda package usage

Because there is an explicit link to libpthread location that breaks visp conda package usage on linux
we cannot use OpenMP_CXX_LIBRARIES that contains /usr/lib/gcc/x86_64-linux-gnu/11/libgomp.so;/usr/lib/x86_64-linux-gnu/libpthread.a
by adding:
list(APPEND opt_libs ${OpenMP_CXX_LIBRARIES})
That's why we need to use the modern way to consider pthread dependency

modules/core/CMakeLists.txt

@@ -232,7 +232,19 @@ if(USE_ZLIB)
 endif()
 if(USE_OPENMP)
   list(APPEND opt_incs ${OpenMP_CXX_INCLUDE_DIRS})
-  list(APPEND opt_libs ${OpenMP_CXX_LIBRARIES})
+  # Because there is an explicit link to libpthread location that breaks visp conda package usage on linux
+  # we cannot use OpenMP_CXX_LIBRARIES that contains /usr/lib/gcc/x86_64-linux-gnu/11/libgomp.so;/usr/lib/x86_64-linux-gnu/libpthread.a
+  # by adding:
+  # list(APPEND opt_libs ${OpenMP_CXX_LIBRARIES})
+  foreach(lib_ ${OpenMP_CXX_LIB_NAMES})
+    if("x${lib_}" STREQUAL "xpthread")
+      if(CMAKE_THREAD_LIBS_INIT)
+        list(APPEND opt_libs "${CMAKE_THREAD_LIBS_INIT}")
+      endif()
+    else()
+      list(APPEND opt_libs ${OpenMP_${lib_}_LIBRARY})
+    endif()
+  endforeach()
 endif()
 if(USE_NLOHMANN_JSON)
   get_target_property(_inc_dirs "nlohmann_json::nlohmann_json" INTERFACE_INCLUDE_DIRECTORIES)