[llvm] [libsycl] add sycl_khr_default_context (PR #216863)

[Kseniya Tikhomirova via llvm-commits]

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@@ -25,9 +25,12 @@
 #include <memory>
 #include <vector>
 
+#define SYCL_KHR_DEFAULT_CONTEXT 1
+
 _LIBSYCL_BEGIN_NAMESPACE_SYCL
 
 class device;
+class context;
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KseniyaTikhomirova wrote:

I believe we should include context.hpp here instead of forward declaration. function signature uses object type not reference or pointer. 

https://github.com/llvm/llvm-project/pull/216863