[compiler-rt] CompilerRT: Normalize COMPILER_RT_DEFAULT_TARGET_TRIPLE (PR #88407)

[Fangrui Song via llvm-commits]

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@@ -362,10 +362,22 @@ macro(construct_compiler_rt_default_triple)
       message(FATAL_ERROR "CMAKE_C_COMPILER_TARGET must also be set when COMPILER_RT_DEFAULT_TARGET_ONLY is ON")
     endif()
     message(STATUS "cmake c compiler target: ${CMAKE_C_COMPILER_TARGET}")
-    set(COMPILER_RT_DEFAULT_TARGET_TRIPLE ${CMAKE_C_COMPILER_TARGET})
+    if ("${CMAKE_C_COMPILER_ID}" MATCHES "Clang")
+      execute_process(COMMAND ${CMAKE_C_COMPILER} -target ${CMAKE_C_COMPILER_TARGET} -print-effective-triple
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MaskRay wrote:

`--target=` instead of long-deprecated `-target `

https://github.com/llvm/llvm-project/pull/88407