Added warning to BLAS.get_num_threads when using Apple Accelerate

Author: ajinkya-k

src/lbt.jl

@@ -221,6 +221,9 @@ function _clear_config_with(f)
 end
 
 function lbt_get_num_threads()
+    if (basename(first(lbt_get_config().loaded_libs).libname) === "Accelerate")
+        @warn "Apple Accelerate does not report number of threads, returning a hardcoded default instead"
+    end
     return ccall((:lbt_get_num_threads, libblastrampoline), Int32, ())
 end