[llvm] [SYCL] Add platform enumeration and info query using liboffload (PR #166927)

[Kseniya Tikhomirova via llvm-commits]

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@@ -41,8 +41,8 @@
 
 #    else // _WIN32
 
-#      define _LIBSYCL_DLL_LOCAL [[__gnu__::__visibility__("hidden")]]
-#      define _LIBSYCL_EXPORT [[__gnu__::__visibility__("default")]]
+#      define _LIBSYCL_DLL_LOCAL __attribute__((visibility("hidden")))
+#      define _LIBSYCL_EXPORT __attribute__((visibility("default")))
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KseniyaTikhomirova wrote:

it seems that gnu::visibility has limitation that attribute (visibility) - don't:
the following code don't compile with old version:
https://github.com/llvm/llvm-project/blob/e8e28110ea51dcf358e7c9f582b43cfea0b5d5ae/libsycl/src/platform.cpp#L36
with
" error: an attribute list cannot appear here"


https://github.com/llvm/llvm-project/pull/166927