PR #1915: Fix SYCL Build Compatibility with Intel LLVM Compiler on Windows for abseil

Imported from GitHub PR https://github.com/abseil/abseil-cpp/pull/1915

Add platform-specific thread-local storage definition for Intel's LLVM compiler when building with SYCL. The Intel LLVM compiler (icx) with  SYCL enabled requires GCC-style thread-local storage (__thread) rather  than Windows-specific __declspec(thread) when compiling for SYCL device code.

This resolves the build error: "thread-local storage is not supported for  the current target" when building with Intel oneAPI env on Windows systems.

Merge 2596bc81e19f8799cf92bd5d36d78aacb0afc9cd into e5266cd1cdd21481209cd55ba7f6698b5fe1bd6b

Merging this change closes #1915

COPYBARA_INTEGRATE_REVIEW=https://github.com/abseil/abseil-cpp/pull/1915 from ContradNamiseb:patch-1 2596bc81e19f8799cf92bd5d36d78aacb0afc9cd
PiperOrigin-RevId: 792213053
Change-Id: Ib53808f0c604749e00ae3da4c9070ab21e19c8d4
diff --git a/absl/base/config.h b/absl/base/config.h
index f3cafbd..b1c5227 100644
--- a/absl/base/config.h
+++ b/absl/base/config.h
@@ -237,6 +237,8 @@
 #error ABSL_HAVE_TLS cannot be directly set
 #elif (defined(__linux__)) && (defined(__clang__) || defined(_GLIBCXX_HAVE_TLS))
 #define ABSL_HAVE_TLS 1
+#elif defined(__INTEL_LLVM_COMPILER)
+#define ABSL_HAVE_TLS 1
 #endif
 
 // ABSL_HAVE_STD_IS_TRIVIALLY_DESTRUCTIBLE