[libc++abi] Stop copying headers to the build directory

This was needed before https://github.com/llvm/llvm-project/pull/115077
since the compiler-rt test build made assumptions about the build
layout of libc++ and libc++abi, but now they link against a local
installation of these libraries so we no longer need this workaround.

Reviewed By: ldionne

Pull Request: https://github.com/llvm/llvm-project/pull/115086

GitOrigin-RevId: 5be02d7a03c6d40d4d71264936d4aab98e4186aa
diff --git a/CMakeLists.txt b/CMakeLists.txt
index da0e8b2..50e9a29 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -86,12 +86,6 @@
 
 set(LIBCXXABI_INSTALL_INCLUDE_DIR "${CMAKE_INSTALL_INCLUDEDIR}/c++/v1" CACHE STRING "Path to install the libc++abi headers at.")
 
-if(LLVM_LIBRARY_OUTPUT_INTDIR)
-  set(LIBCXXABI_GENERATED_INCLUDE_DIR "${LLVM_BINARY_DIR}/include/c++/v1")
-else()
-  set(LIBCXXABI_GENERATED_INCLUDE_DIR "${CMAKE_BINARY_DIR}/include/c++/v1")
-endif()
-
 set(LIBCXXABI_LIBCXX_LIBRARY_PATH "" CACHE PATH "The path to libc++ library.")
 set(LIBCXXABI_LIBRARY_VERSION "1.0" CACHE STRING
 "Version of libc++abi. This will be reflected in the name of the shared \
diff --git a/include/CMakeLists.txt b/include/CMakeLists.txt
index 5b1cc25..0deb7b1 100644
--- a/include/CMakeLists.txt
+++ b/include/CMakeLists.txt
@@ -3,20 +3,7 @@
   cxxabi.h
   )
 
-foreach(f ${files})
-  set(src "${CMAKE_CURRENT_SOURCE_DIR}/${f}")
-  set(dst "${LIBCXXABI_GENERATED_INCLUDE_DIR}/${f}")
-  add_custom_command(OUTPUT ${dst}
-    DEPENDS ${src}
-    COMMAND ${CMAKE_COMMAND} -E copy_if_different ${src} ${dst}
-    COMMENT "Copying CXXABI header ${f}")
-  list(APPEND _all_includes "${dst}")
-endforeach()
-
-add_custom_target(generate-cxxabi-headers ALL DEPENDS ${_all_includes})
-
 add_library(cxxabi-headers INTERFACE)
-add_dependencies(cxxabi-headers generate-cxxabi-headers)
 target_include_directories(cxxabi-headers INTERFACE "${CMAKE_CURRENT_SOURCE_DIR}")
 
 if (LIBCXXABI_INSTALL_HEADERS)