[PATCH] D88157: [CMake] Make sure _cmake_system_name has a default

[Petr Hosek via Phabricator via llvm-commits]

phosek added a comment.

This broke our macOS builders because now `llvm-libtool-darwin` tool is being used by default which leads to a build failure:

  Merging archives: ['/b/s/w/ir/x/w/staging/llvm_build/lib/libc++abi.a', '/b/s/w/ir/x/w/staging/llvm_build/lib/libunwind.a']
  Command: '/b/s/w/ir/x/w/staging/llvm_build/bin/llvm-libtool-darwin' '-static' '-o' '/b/s/w/ir/x/w/staging/llvm_build/lib/libc++abi.a' '-s' 'cxa_aux_runtime.cpp.o' 'cxa_default_handlers.cpp.o' 'cxa_demangle.cpp.o' 'cxa_exception_storage.cpp.o' 'cxa_guard.cpp.o' 'cxa_handlers.cpp.o' 'cxa_vector.cpp.o' 'cxa_virtual.cpp.o' 'stdlib_exception.cpp.o' 'stdlib_stdexcept.cpp.o' 'stdlib_typeinfo.cpp.o' 'abort_message.cpp.o' 'fallback_malloc.cpp.o' 'private_typeinfo.cpp.o' 'stdlib_new_delete.cpp.o' 'cxa_exception.cpp.o' 'cxa_personality.cpp.o' 'libunwind.cpp.o' 'Unwind-EHABI.cpp.o' 'Unwind-seh.cpp.o' 'Unwind_AppleExtras.cpp.o' 'UnwindLevel1.c.o' 'UnwindLevel1-gcc-ext.c.o' 'Unwind-sjlj.c.o' 'UnwindRegistersRestore.S.o' 'UnwindRegistersSave.S.o'
  Exit Code: 1
  Standard Error:
  --
  llvm-libtool-darwin: Unknown command line argument '-s'.  Try: '/b/s/w/ir/x/w/staging/llvm_build/bin/llvm-libtool-darwin --help'
  llvm-libtool-darwin: Did you mean '-D'?
  --


Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D88157/new/

https://reviews.llvm.org/D88157