I maintain a dynamic library built on JUCE, and primarily develop on Windows, but I support Android and OSX as well. After updating JUCE to the develop branch last week (from a version over 1.5 years old), I get an error when trying to link my project:

Undefined symbols for architecture x86_64:
  "_OBJC_CLASS_$_MTLTextureDescriptor", referenced from:
      objc-class-ref in include_juce_gui_basics.o

Any advice would be greatly appreciated. Thanks!

I should note that I am including the Metal and MetalKit frameworks in my xcode project

Have you tried a clean build ?

Yep, doesn’t fix

Are you definitely linking your final build artefact to the Metal + MetalKit frameworks?