Conda forge fix (#46)

* fixed bug where cks were using interval scope

* added a fix for conda-forge

CMakeLists.txt

@@ -11,6 +11,9 @@ set(CMAKE_CXX_STANDARD 20)
 
 set(CMAKE_CXX_STANDARD_REQUIRED ON)
 
+# to avoid complaints in conda-forge, see https://conda-forge.org/docs/maintainer/knowledge_base/#newer-c-features-with-old-sdk 
+set(CXXFLAGS, "${CXXFLAGS} -D_LIBCPP_DISABLE_AVAILABILITY")
+
 # Set up Anaconda prefix in the case with a non-default conda env is activated
 if(EXISTS $ENV{CONDA_PREFIX})
   message("CONDA PREFIX: $ENV{CONDA_PREFIX}")