llvm-capstone/libcxxabi/CMakeLists.txt

#===============================================================================
# Setup Project
#===============================================================================

cmake_minimum_required(VERSION 3.4.3)

if(POLICY CMP0042)
  cmake_policy(SET CMP0042 NEW) # Set MACOSX_RPATH=YES by default
endif()

if (CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR)
  project(libcxxabi)

  # Rely on llvm-config.
  set(CONFIG_OUTPUT)
  if (NOT LLVM_CONFIG_PATH)
    find_program(LLVM_CONFIG_PATH "llvm-config")
  endif()
  if(DEFINED LLVM_PATH)
    set(LLVM_INCLUDE_DIR ${LLVM_INCLUDE_DIR} CACHE PATH "Path to llvm/include")
    set(LLVM_PATH ${LLVM_PATH} CACHE PATH "Path to LLVM source tree")
    set(LLVM_MAIN_SRC_DIR ${LLVM_PATH})
    set(LLVM_CMAKE_PATH "${LLVM_PATH}/cmake/modules")
  elseif(LLVM_CONFIG_PATH)
    message(STATUS "Found LLVM_CONFIG_PATH as ${LLVM_CONFIG_PATH}")
    set(CONFIG_COMMAND ${LLVM_CONFIG_PATH}
      "--includedir"
      "--prefix"
      "--src-root")
    execute_process(
      COMMAND ${CONFIG_COMMAND}
      RESULT_VARIABLE HAD_ERROR
      OUTPUT_VARIABLE CONFIG_OUTPUT
    )
    if(NOT HAD_ERROR)
      string(REGEX REPLACE
        "[ \t]*[\r\n]+[ \t]*" ";"
        CONFIG_OUTPUT ${CONFIG_OUTPUT})
    else()
      string(REPLACE ";" " " CONFIG_COMMAND_STR "${CONFIG_COMMAND}")
      message(STATUS "${CONFIG_COMMAND_STR}")
      message(FATAL_ERROR "llvm-config failed with status ${HAD_ERROR}")
    endif()

    list(GET CONFIG_OUTPUT 0 INCLUDE_DIR)
    list(GET CONFIG_OUTPUT 1 LLVM_OBJ_ROOT)
    list(GET CONFIG_OUTPUT 2 MAIN_SRC_DIR)

    set(LLVM_INCLUDE_DIR ${INCLUDE_DIR} CACHE PATH "Path to llvm/include")
    set(LLVM_BINARY_DIR ${LLVM_OBJ_ROOT} CACHE PATH "Path to LLVM build tree")
    set(LLVM_MAIN_SRC_DIR ${MAIN_SRC_DIR} CACHE PATH "Path to LLVM source tree")
    set(LLVM_CMAKE_PATH "${LLVM_BINARY_DIR}/lib${LLVM_LIBDIR_SUFFIX}/cmake/llvm")
    set(LLVM_LIT_PATH "${LLVM_PATH}/utils/lit/lit.py")
  else()
    message(FATAL_ERROR "llvm-config not found and LLVM_MAIN_SRC_DIR not defined. "
                        "Reconfigure with -DLLVM_CONFIG_PATH=path/to/llvm-config "
                        "or -DLLVM_PATH=path/to/llvm-source-root.")
  endif()

  if(EXISTS ${LLVM_CMAKE_PATH})
    list(APPEND CMAKE_MODULE_PATH "${LLVM_CMAKE_PATH}")
    include("${LLVM_CMAKE_PATH}/AddLLVM.cmake")
    include("${LLVM_CMAKE_PATH}/HandleLLVMOptions.cmake")
  else()
    message(FATAL_ERROR "Not found: ${LLVM_CMAKE_PATH}")
  endif()

  set(PACKAGE_NAME libcxxabi)
  set(PACKAGE_VERSION 4.0.0svn)
  set(PACKAGE_STRING "${PACKAGE_NAME} ${PACKAGE_VERSION}")
  set(PACKAGE_BUGREPORT "llvm-bugs@lists.llvm.org")

  if(EXISTS ${LLVM_MAIN_SRC_DIR}/utils/lit/lit.py)
    set(LLVM_LIT ${LLVM_MAIN_SRC_DIR}/utils/lit/lit.py)
  else()
    # Seek installed Lit.
    find_program(LLVM_LIT "lit.py" ${LLVM_MAIN_SRC_DIR}/utils/lit
      DOC "Path to lit.py")
  endif()

  if(LLVM_LIT)
    # Define the default arguments to use with 'lit', and an option for the user
    # to override.
    set(LIT_ARGS_DEFAULT "-sv")
    if (MSVC OR XCODE)
      set(LIT_ARGS_DEFAULT "${LIT_ARGS_DEFAULT} --no-progress-bar")
    endif()
    set(LLVM_LIT_ARGS "${LIT_ARGS_DEFAULT}" CACHE STRING "Default options for lit")

    # On Win32 hosts, provide an option to specify the path to the GnuWin32 tools.
    if( WIN32 AND NOT CYGWIN )
      set(LLVM_LIT_TOOLS_DIR "" CACHE PATH "Path to GnuWin32 tools")
    endif()
  else()
    set(LLVM_INCLUDE_TESTS OFF)
  endif()

  set(LIBCXXABI_LIBDIR_SUFFIX "${LLVM_LIBDIR_SUFFIX}" CACHE STRING
      "Define suffix of library directory name (32/64)")

  set(LIBCXXABI_STANDALONE_BUILD 1)
else()
  set(LLVM_MAIN_SRC_DIR "${CMAKE_SOURCE_DIR}" CACHE PATH "Path to LLVM source tree")
  set(LLVM_LIT "${CMAKE_SOURCE_DIR}/utils/lit/lit.py")
  set(LIBCXXABI_LIBDIR_SUFFIX ${LLVM_LIBDIR_SUFFIX})
endif()

#===============================================================================
# Setup CMake Options
#===============================================================================

# Define options.
option(LIBCXXABI_ENABLE_EXCEPTIONS "Use exceptions." ON)
option(LIBCXXABI_ENABLE_ASSERTIONS "Enable assertions independent of build mode." ON)
option(LIBCXXABI_ENABLE_PEDANTIC "Compile with pedantic enabled." ON)
option(LIBCXXABI_ENABLE_WERROR "Fail and stop if a warning is triggered." OFF)
option(LIBCXXABI_USE_LLVM_UNWINDER "Build and use the LLVM unwinder." OFF)
option(LIBCXXABI_USE_COMPILER_RT "Use compiler-rt instead of libgcc" OFF)
option(LIBCXXABI_ENABLE_THREADS "Build with threads enabled" ON)
option(LIBCXXABI_HAS_PTHREAD_API "Ignore auto-detection and force use of pthread API" OFF)
option(LIBCXXABI_BUILD_32_BITS "Build 32 bit libc++abi." ${LLVM_BUILD_32_BITS})
set(LIBCXXABI_TARGET_TRIPLE "" CACHE STRING "Target triple for cross compiling.")
set(LIBCXXABI_GCC_TOOLCHAIN "" CACHE PATH "GCC toolchain for cross compiling.")
set(LIBCXXABI_SYSROOT "" CACHE PATH "Sysroot for cross compiling.")
set(LIBCXXABI_LIBCXX_LIBRARY_PATH "" CACHE PATH "The path to libc++ library.")

# Default to building a shared library so that the default options still test
# the libc++abi that is being built. There are two problems with testing a
# static libc++abi. In the case of a standalone build, the tests will link the
# system's libc++, which might not have been built against our libc++abi. In the
# case of an in tree build, libc++ will prefer a dynamic libc++abi from the
# system over a static libc++abi from the output directory.
option(LIBCXXABI_ENABLE_SHARED "Build libc++abi as a shared library." ON)
option(LIBCXXABI_ENABLE_STATIC "Build libc++abi as a static library." ON)

if (NOT LIBCXXABI_ENABLE_SHARED AND NOT LIBCXXABI_ENABLE_STATIC)
  message(FATAL_ERROR "libc++abi must be built as either a shared or static library.")
endif()

if (LLVM_EXTERNAL_LIBCXX_SOURCE_DIR)
  set(LIBCXXABI_LIBCXX_SRC_DIRS ${LLVM_EXTERNAL_LIBCXX_SOURCE_DIR})
else()
  set(LIBCXXABI_LIBCXX_SRC_DIRS
    "${LLVM_MAIN_SRC_DIR}/projects/libcxx"
    "${LLVM_MAIN_SRC_DIR}/runtimes/libcxx"
    )
endif()

set(LIBCXXABI_LIBCXX_INCLUDE_DIRS "")
foreach(dir ${LIBCXXABI_LIBCXX_SRC_DIRS})
  list(APPEND LIBCXXABI_LIBCXX_INCLUDE_DIRS "${dir}/include")
endforeach()

find_path(
  LIBCXXABI_LIBCXX_INCLUDES
  vector
  PATHS ${LIBCXXABI_LIBCXX_INCLUDES}
        ${LIBCXXABI_LIBCXX_PATH}/include
        ${CMAKE_BINARY_DIR}/${LIBCXXABI_LIBCXX_INCLUDES}
        ${LIBCXXABI_LIBCXX_INCLUDE_DIRS}
        ${LLVM_INCLUDE_DIR}/c++/v1
  )

set(LIBCXXABI_LIBCXX_INCLUDES "${LIBCXXABI_LIBCXX_INCLUDES}" CACHE PATH
    "Specify path to libc++ includes." FORCE)

find_path(
  LIBCXXABI_LIBCXX_PATH
  test/libcxx/__init__.py
  PATHS ${LIBCXXABI_LIBCXX_PATH}
        ${LIBCXXABI_LIBCXX_INCLUDES}/../
        ${LIBCXXABI_LIBCXX_SRC_DIRS}
  NO_DEFAULT_PATH
  )

if (LIBCXXABI_LIBCXX_PATH STREQUAL "LIBCXXABI_LIBCXX_PATH-NOTFOUND")
  message(WARNING "LIBCXXABI_LIBCXX_PATH was not specified and couldn't be infered.")
  set(LIBCXXABI_LIBCXX_PATH "")
endif()

set(LIBCXXABI_LIBCXX_PATH "${LIBCXXABI_LIBCXX_PATH}" CACHE PATH
    "Specify path to libc++ source." FORCE)

#===============================================================================
# Configure System
#===============================================================================

# Add path for custom modules
set(CMAKE_MODULE_PATH
  "${CMAKE_CURRENT_SOURCE_DIR}/cmake"
  "${CMAKE_CURRENT_SOURCE_DIR}/cmake/Modules"
  ${CMAKE_MODULE_PATH}
  )

set(LIBCXXABI_COMPILER    ${CMAKE_CXX_COMPILER})
set(LIBCXXABI_SOURCE_DIR  ${CMAKE_CURRENT_SOURCE_DIR})
set(LIBCXXABI_BINARY_DIR  ${CMAKE_CURRENT_BINARY_DIR})
set(LIBCXXABI_LIBRARY_DIR ${CMAKE_BINARY_DIR}/lib${LIBCXXABI_LIBDIR_SUFFIX})

set(CMAKE_ARCHIVE_OUTPUT_DIRECTORY ${LIBCXXABI_LIBRARY_DIR})
set(CMAKE_LIBRARY_OUTPUT_DIRECTORY ${LIBCXXABI_LIBRARY_DIR})

# By default, for non-standalone builds, libcxx and libcxxabi share a library
# directory.
if (NOT LIBCXXABI_LIBCXX_LIBRARY_PATH)
  set(LIBCXXABI_LIBCXX_LIBRARY_PATH "${LIBCXXABI_LIBRARY_DIR}" CACHE PATH
      "The path to libc++ library.")
endif()

# Check that we can build with 32 bits if requested.
if (CMAKE_SIZEOF_VOID_P EQUAL 8 AND NOT WIN32)
  if (LIBCXXABI_BUILD_32_BITS AND NOT LLVM_BUILD_32_BITS) # Don't duplicate the output from LLVM
    message(STATUS "Building 32 bits executables and libraries.")
  endif()
elseif(LIBCXXABI_BUILD_32_BITS)
  message(FATAL_ERROR "LIBCXXABI_BUILD_32_BITS=ON is not supported on this platform.")
endif()

#===============================================================================
# Setup Compiler Flags
#===============================================================================

# Get required flags.
macro(append_if list condition var)
  if (${condition})
    list(APPEND ${list} ${var})
  endif()
endmacro()

macro(add_target_flags_if condition var)
  if (${condition})
    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${var}")
    set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} ${var}")
    list(APPEND LIBCXXABI_LINK_FLAGS ${var})
  endif()
endmacro()

set(LIBCXXABI_C_FLAGS "")
set(LIBCXXABI_CXX_FLAGS "")
set(LIBCXXABI_COMPILE_FLAGS "")
set(LIBCXXABI_LINK_FLAGS "")

# Configure target flags
add_target_flags_if(LIBCXXABI_BUILD_32_BITS "-m32")
add_target_flags_if(LIBCXXABI_TARGET_TRIPLE
          "-target ${LIBCXXABI_TARGET_TRIPLE}")
add_target_flags_if(LIBCXXABI_GCC_TOOLCHAIN
         "-gcc-toolchain ${LIBCXXABI_GCC_TOOLCHAIN}")
add_target_flags_if(LIBCXXABI_SYSROOT
          "--sysroot=${LIBCXXABI_SYSROOT}")

# Configure compiler. Must happen after setting the target flags.
include(config-ix)

if (LIBCXXABI_HAS_NOSTDINCXX_FLAG)
  list(APPEND LIBCXXABI_COMPILE_FLAGS -nostdinc++)
  # Remove -stdlib flags to prevent them from causing an unused flag warning.
  string(REPLACE "-stdlib=libc++" "" CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS}")
  string(REPLACE "-stdlib=libstdc++" "" CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS}")
endif()

if (LIBCXXABI_USE_COMPILER_RT)
  list(APPEND LIBCXXABI_LINK_FLAGS "-rtlib=compiler-rt")
endif()

# Let the library headers know they are currently being used to build the
# library.
add_definitions(-D_LIBCXXABI_BUILDING_LIBRARY)

# Disable DLL annotations on Windows for static builds.
if (WIN32 AND LIBCXXABI_ENABLE_STATIC AND NOT LIBCXXABI_ENABLE_SHARED)
  add_definitions(-D_LIBCXXABI_DISABLE_DLL_IMPORT_EXPORT)
endif()

append_if(LIBCXXABI_COMPILE_FLAGS LIBCXXABI_HAS_WERROR_FLAG -Werror=return-type)

# Get warning flags
append_if(LIBCXXABI_COMPILE_FLAGS LIBCXXABI_HAS_W_FLAG -W)
append_if(LIBCXXABI_COMPILE_FLAGS LIBCXXABI_HAS_WALL_FLAG -Wall)
append_if(LIBCXXABI_COMPILE_FLAGS LIBCXXABI_HAS_WCHAR_SUBSCRIPTS_FLAG -Wchar-subscripts)
append_if(LIBCXXABI_COMPILE_FLAGS LIBCXXABI_HAS_WCONVERSION_FLAG -Wconversion)
append_if(LIBCXXABI_COMPILE_FLAGS LIBCXXABI_HAS_WMISMATCHED_TAGS_FLAG -Wmismatched-tags)
append_if(LIBCXXABI_COMPILE_FLAGS LIBCXXABI_HAS_WMISSING_BRACES_FLAG -Wmissing-braces)
append_if(LIBCXXABI_COMPILE_FLAGS LIBCXXABI_HAS_WNEWLINE_EOF_FLAG -Wnewline-eof)
append_if(LIBCXXABI_COMPILE_FLAGS LIBCXXABI_HAS_WNO_UNUSED_FUNCTION_FLAG -Wno-unused-function)
append_if(LIBCXXABI_COMPILE_FLAGS LIBCXXABI_HAS_WSHADOW_FLAG -Wshadow)
append_if(LIBCXXABI_COMPILE_FLAGS LIBCXXABI_HAS_WSHORTEN_64_TO_32_FLAG -Wshorten-64-to-32)
append_if(LIBCXXABI_COMPILE_FLAGS LIBCXXABI_HAS_WSIGN_COMPARE_FLAG -Wsign-compare)
append_if(LIBCXXABI_COMPILE_FLAGS LIBCXXABI_HAS_WSIGN_CONVERSION_FLAG -Wsign-conversion)
append_if(LIBCXXABI_COMPILE_FLAGS LIBCXXABI_HAS_WSTRICT_ALIASING_FLAG -Wstrict-aliasing=2)
append_if(LIBCXXABI_COMPILE_FLAGS LIBCXXABI_HAS_WSTRICT_OVERFLOW_FLAG -Wstrict-overflow=4)
append_if(LIBCXXABI_COMPILE_FLAGS LIBCXXABI_HAS_WUNUSED_PARAMETER_FLAG -Wunused-parameter)
append_if(LIBCXXABI_COMPILE_FLAGS LIBCXXABI_HAS_WUNUSED_VARIABLE_FLAG -Wunused-variable)
append_if(LIBCXXABI_COMPILE_FLAGS LIBCXXABI_HAS_WWRITE_STRINGS_FLAG -Wwrite-strings)
append_if(LIBCXXABI_COMPILE_FLAGS LIBCXXABI_HAS_WUNDEF_FLAG -Wundef)

if (LIBCXXABI_ENABLE_WERROR)
  append_if(LIBCXXABI_COMPILE_FLAGS LIBCXXABI_HAS_WERROR_FLAG -Werror)
  append_if(LIBCXXABI_COMPILE_FLAGS LIBCXXABI_HAS_WX_FLAG -WX)
else()
  append_if(LIBCXXABI_COMPILE_FLAGS LIBCXXABI_HAS_WNO_ERROR_FLAG -Wno-error)
  append_if(LIBCXXABI_COMPILE_FLAGS LIBCXXABI_HAS_NO_WX_FLAG -WX-)
endif()
if (LIBCXXABI_ENABLE_PEDANTIC)
  append_if(LIBCXXABI_COMPILE_FLAGS LIBCXXABI_HAS_PEDANTIC_FLAG -pedantic)
endif()

# Get feature flags.
append_if(LIBCXXABI_CXX_FLAGS LIBCXXABI_HAS_FSTRICT_ALIASING_FLAG -fstrict-aliasing)

# Exceptions
if (LIBCXXABI_ENABLE_EXCEPTIONS)
  # Catches C++ exceptions only and tells the compiler to assume that extern C
  # functions never throw a C++ exception.
  append_if(LIBCXXABI_CXX_FLAGS LIBCXXABI_HAS_EHSC_FLAG -EHsc)
  append_if(LIBCXXABI_C_FLAGS LIBCXXABI_HAS_FUNWIND_TABLES -funwind-tables)
else()
  add_definitions(-D_LIBCXXABI_NO_EXCEPTIONS)
  append_if(LIBCXXABI_CXX_FLAGS LIBCXXABI_HAS_NO_EXCEPTIONS_FLAG -fno-exceptions)
  append_if(LIBCXXABI_CXX_FLAGS LIBCXXABI_HAS_NO_EHS_FLAG -EHs-)
  append_if(LIBCXXABI_CXX_FLAGS LIBCXXABI_HAS_NO_EHA_FLAG -EHa-)
endif()

# Assert
string(TOUPPER "${CMAKE_BUILD_TYPE}" uppercase_CMAKE_BUILD_TYPE)
if (LIBCXXABI_ENABLE_ASSERTIONS)
  # MSVC doesn't like _DEBUG on release builds. See PR 4379.
  if (NOT MSVC)
    list(APPEND LIBCXXABI_COMPILE_FLAGS -D_DEBUG)
  endif()
  # On Release builds cmake automatically defines NDEBUG, so we
  # explicitly undefine it:
  if (uppercase_CMAKE_BUILD_TYPE STREQUAL "RELEASE")
    list(APPEND LIBCXXABI_COMPILE_FLAGS -UNDEBUG)
  endif()
else()
  if (NOT uppercase_CMAKE_BUILD_TYPE STREQUAL "RELEASE")
    list(APPEND LIBCXXABI_COMPILE_FLAGS -DNDEBUG)
  endif()
endif()
# Static library
if (NOT LIBCXXABI_ENABLE_SHARED)
  list(APPEND LIBCXXABI_COMPILE_FLAGS -D_LIBCPP_BUILD_STATIC)
endif()

if (NOT LIBCXXABI_ENABLE_THREADS)
  if (LIBCXXABI_HAS_PTHREAD_API)
    message(FATAL_ERROR "LIBCXXABI_HAS_PTHREAD_API can only"
                        " be set to ON when LIBCXXABI_ENABLE_THREADS"
                        " is also set to ON.")
  endif()
  add_definitions(-D_LIBCXXABI_HAS_NO_THREADS)
endif()

if (LIBCXXABI_HAS_PTHREAD_API)
  add_definitions(-D_LIBCPP_HAS_THREAD_API_PTHREAD)
  add_definitions(-D_LIBCXXABI_USE_THREAD_API_PTHREAD)
endif()

if (MSVC)
  add_definitions(-D_CRT_SECURE_NO_WARNINGS)
endif()

# Define LIBCXXABI_USE_LLVM_UNWINDER for conditional compilation.
if (LIBCXXABI_USE_LLVM_UNWINDER)
  add_definitions(-DLIBCXXABI_USE_LLVM_UNWINDER=1)
endif()

string(REPLACE ";" " " LIBCXXABI_CXX_FLAGS "${LIBCXXABI_CXX_FLAGS}")
set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${LIBCXXABI_CXX_FLAGS}")
set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} ${LIBCXXABI_C_FLAGS}")

#===============================================================================
# Setup Source Code
#===============================================================================

set(LIBCXXABI_LIBUNWIND_INCLUDES "${LIBCXXABI_LIBUNWIND_INCLUDES}" CACHE PATH
    "Specify path to libunwind includes." FORCE)
set(LIBCXXABI_LIBUNWIND_PATH "${LIBCXXABI_LIBUNWIND_PATH}" CACHE PATH
    "Specify path to libunwind source." FORCE)

include_directories(include)
if (LIBCXXABI_USE_LLVM_UNWINDER OR LLVM_NATIVE_ARCH MATCHES ARM)
  find_path(
    LIBCXXABI_LIBUNWIND_INCLUDES_INTERNAL
    libunwind.h
    PATHS ${LIBCXXABI_LIBUNWIND_INCLUDES}
          ${LIBCXXABI_LIBUNWIND_PATH}/include
          ${CMAKE_BINARY_DIR}/${LIBCXXABI_LIBUNWIND_INCLUDES}
          ${LLVM_MAIN_SRC_DIR}/projects/libunwind/include
          ${LLVM_MAIN_SRC_DIR}/runtimes/libunwind/include
    NO_DEFAULT_PATH
  )

  find_path(
    LIBCXXABI_LIBUNWIND_SOURCES
    libunwind_ext.h
    PATHS ${LIBCXXABI_LIBUNWIND_PATH}/src/
          ${LIBCXXABI_LIBUNWIND_INCLUDES}/../src/
          ${LLVM_MAIN_SRC_DIR}/projects/libunwind/src/
          ${LLVM_MAIN_SRC_DIR}/runtimes/libunwind/src/
    NO_DEFAULT_PATH
  )

  if (LIBCXXABI_LIBUNWIND_SOURCES STREQUAL "LIBCXXABI_LIBUNWIND_SOURCES-NOTFOUND")
    message(WARNING "LIBCXXABI_LIBUNWIND_SOURCES was not specified and couldn't be infered.")
    set(LIBCXXABI_LIBUNWIND_SOURCES "")
  endif()

  include_directories("${LIBCXXABI_LIBUNWIND_INCLUDES_INTERNAL}")
  include_directories("${LIBCXXABI_LIBUNWIND_SOURCES}")
endif()

# Add source code. This also contains all of the logic for deciding linker flags
# soname, etc...
add_subdirectory(src)

if (LIBCXXABI_STANDALONE_BUILD AND NOT LIBCXXABI_ENABLE_SHARED)
  # We can't reasonably test the system C++ library with a static libc++abi.
  # We either need to be able to replace libc++abi at run time (with a shared
  # libc++abi), or we need to be able to replace the C++ runtime (with a non-
  # standalone build).
  message(WARNING "The libc++abi tests aren't valid when libc++abi is built "
                  "standalone (i.e. outside of llvm/projects/libcxxabi ) and "
                  "is built without a shared library.  Either build a shared "
                  "library, build libc++abi at the same time as you build "
                  "libc++, or do without testing.  No check target will be "
                  "available!")
else()
  add_subdirectory(test)
endif()