diff --git a/libunwind/cmake/config-ix.cmake b/libunwind/cmake/config-ix.cmake
--- a/libunwind/cmake/config-ix.cmake
+++ b/libunwind/cmake/config-ix.cmake
@@ -35,7 +35,7 @@
 if (CXX_SUPPORTS_NOSTDLIBXX_FLAG)
   set(CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS} -nostdlib++")
 else()
-  llvm_check_compiler_linker_flag(C "-nodefaultlibs" LIBUNWIND_SUPPORTS_NODEFAULTLIBS_FLAG)
+  llvm_check_compiler_linker_flag(C "-nodefaultlibs" C_SUPPORTS_NODEFAULTLIBS_FLAG)
   if (C_SUPPORTS_NODEFAULTLIBS_FLAG)
     set(CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS} -nodefaultlibs")
   endif()