[llvm] [runtimes] remove workaround for old CMake when setting `--unwindlib=none` (PR #93429)

[via llvm-commits]

https://github.com/h-vetinari created https://github.com/llvm/llvm-project/pull/93429

Noticed a left-over for old CMake, irrelevant now that the baseline version moved to 3.20.

>From c8a0b127ade4330151951144f6d4841beaf66d23 Mon Sep 17 00:00:00 2001
From: "H. Vetinari" <h.vetinari at gmx.com>
Date: Sun, 26 May 2024 13:21:46 +1100
Subject: [PATCH] [runtimes] remove workaround for old CMake when setting
 `--unwindlib=none`

---
 runtimes/CMakeLists.txt | 22 +---------------------
 1 file changed, 1 insertion(+), 21 deletions(-)

diff --git a/runtimes/CMakeLists.txt b/runtimes/CMakeLists.txt
index 24f4851169591..15f9334776e05 100644
--- a/runtimes/CMakeLists.txt
+++ b/runtimes/CMakeLists.txt
@@ -116,27 +116,7 @@ filter_prefixed("${CMAKE_ASM_IMPLICIT_INCLUDE_DIRECTORIES}" ${LLVM_BINARY_DIR} C
 # brittle. We should ideally move this to runtimes/CMakeLists.txt.
 llvm_check_compiler_linker_flag(C "--unwindlib=none" CXX_SUPPORTS_UNWINDLIB_EQ_NONE_FLAG)
 if (CXX_SUPPORTS_UNWINDLIB_EQ_NONE_FLAG)
-  set(ORIG_CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS}")
-  set(CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS} --unwindlib=none")
-  # TODO: When we can require CMake 3.14, we should use
-  # CMAKE_REQUIRED_LINK_OPTIONS here. Until then, we need a workaround:
-  # When using CMAKE_REQUIRED_FLAGS, this option gets added both to
-  # compilation and linking commands. That causes warnings in the
-  # compilation commands during cmake tests. This is normally benign, but
-  # when testing whether -Werror works, that test fails (due to the
-  # preexisting warning).
-  #
-  # Therefore, before we can use CMAKE_REQUIRED_LINK_OPTIONS, check if we
-  # can use --start-no-unused-arguments to silence the warnings about
-  # --unwindlib=none during compilation.
-  #
-  # We must first add --unwindlib=none to CMAKE_REQUIRED_FLAGS above, to
-  # allow this subsequent test to succeed, then rewrite CMAKE_REQUIRED_FLAGS
-  # below.
-  check_c_compiler_flag("--start-no-unused-arguments" C_SUPPORTS_START_NO_UNUSED_ARGUMENTS)
-  if (C_SUPPORTS_START_NO_UNUSED_ARGUMENTS)
-    set(CMAKE_REQUIRED_FLAGS "${ORIG_CMAKE_REQUIRED_FLAGS} --start-no-unused-arguments --unwindlib=none --end-no-unused-arguments")
-  endif()
+  set(CMAKE_REQUIRED_LINK_OPTIONS "${CMAKE_REQUIRED_LINK_OPTIONS} --unwindlib=none")
 endif()
 
 # Disable use of the installed C++ standard library when building runtimes.