[llvm] [SYCL] Add libsycl, a SYCL RT library implementation project (PR #144372)

[Kseniya Tikhomirova via llvm-commits]

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@@ -0,0 +1 @@
+BasedOnStyle: LLVM
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KseniyaTikhomirova wrote:

I don't see it to be set in any other runtime (and any other project either). It doesn't seem right to differ in style from other runtimes.

https://github.com/llvm/llvm-project/pull/144372