Modules/Platform/Darwin.cmake - third_party/cmake - Git at Google

 SET(APPLE 1)

 # Darwin versions:
 #   6.x == Mac OSX 10.2 (Jaguar)
 #   7.x == Mac OSX 10.3 (Panther)
 #   8.x == Mac OSX 10.4 (Tiger)
 #   9.x == Mac OSX 10.5 (Leopard)
 #  10.x == Mac OSX 10.6 (Snow Leopard)
 #  11.x == Mac OSX 10.7 (Lion)
 #  12.x == Mac OSX 10.8 (Mountain Lion)
 STRING(REGEX REPLACE "^([0-9]+)\\.([0-9]+).*$" "\\1" DARWIN_MAJOR_VERSION "${CMAKE_SYSTEM_VERSION}")
 STRING(REGEX REPLACE "^([0-9]+)\\.([0-9]+).*$" "\\2" DARWIN_MINOR_VERSION "${CMAKE_SYSTEM_VERSION}")

 # Do not use the "-Wl,-search_paths_first" flag with the OSX 10.2 compiler.
 # Done this way because it is too early to do a TRY_COMPILE.
 IF(NOT DEFINED HAVE_FLAG_SEARCH_PATHS_FIRST)
   SET(HAVE_FLAG_SEARCH_PATHS_FIRST 0)
   IF("${DARWIN_MAJOR_VERSION}" GREATER 6)
     SET(HAVE_FLAG_SEARCH_PATHS_FIRST 1)
   ENDIF("${DARWIN_MAJOR_VERSION}" GREATER 6)
 ENDIF(NOT DEFINED HAVE_FLAG_SEARCH_PATHS_FIRST)
 # More desirable, but does not work:
   #INCLUDE(CheckCXXCompilerFlag)
   #CHECK_CXX_COMPILER_FLAG("-Wl,-search_paths_first" HAVE_FLAG_SEARCH_PATHS_FIRST)

 SET(CMAKE_SHARED_LIBRARY_PREFIX "lib")
 SET(CMAKE_SHARED_LIBRARY_SUFFIX ".dylib")
 SET(CMAKE_SHARED_MODULE_PREFIX "lib")
 SET(CMAKE_SHARED_MODULE_SUFFIX ".so")
 SET(CMAKE_MODULE_EXISTS 1)
 SET(CMAKE_DL_LIBS "")

 SET(CMAKE_C_OSX_COMPATIBILITY_VERSION_FLAG "-compatibility_version ")
 SET(CMAKE_C_OSX_CURRENT_VERSION_FLAG "-current_version ")
 SET(CMAKE_CXX_OSX_COMPATIBILITY_VERSION_FLAG "${CMAKE_C_OSX_COMPATIBILITY_VERSION_FLAG}")
 SET(CMAKE_CXX_OSX_CURRENT_VERSION_FLAG "${CMAKE_C_OSX_CURRENT_VERSION_FLAG}")

 SET(CMAKE_C_LINK_FLAGS "-Wl,-headerpad_max_install_names")
 SET(CMAKE_CXX_LINK_FLAGS "-Wl,-headerpad_max_install_names")

 IF(HAVE_FLAG_SEARCH_PATHS_FIRST)
   SET(CMAKE_C_LINK_FLAGS "-Wl,-search_paths_first ${CMAKE_C_LINK_FLAGS}")
   SET(CMAKE_CXX_LINK_FLAGS "-Wl,-search_paths_first ${CMAKE_CXX_LINK_FLAGS}")
 ENDIF(HAVE_FLAG_SEARCH_PATHS_FIRST)

 SET(CMAKE_PLATFORM_HAS_INSTALLNAME 1)
 SET(CMAKE_SHARED_LIBRARY_CREATE_C_FLAGS "-dynamiclib -Wl,-headerpad_max_install_names")
 SET(CMAKE_SHARED_MODULE_CREATE_C_FLAGS "-bundle -Wl,-headerpad_max_install_names")
 SET(CMAKE_SHARED_MODULE_LOADER_C_FLAG "-Wl,-bundle_loader,")
 SET(CMAKE_SHARED_MODULE_LOADER_CXX_FLAG "-Wl,-bundle_loader,")
 SET(CMAKE_FIND_LIBRARY_SUFFIXES ".dylib" ".so" ".a")

 # hack: if a new cmake (which uses CMAKE_INSTALL_NAME_TOOL) runs on an old build tree
 # (where install_name_tool was hardcoded) and where CMAKE_INSTALL_NAME_TOOL isn't in the cache
 # and still cmake didn't fail in CMakeFindBinUtils.cmake (because it isn't rerun)
 # hardcode CMAKE_INSTALL_NAME_TOOL here to install_name_tool, so it behaves as it did before, Alex
 IF(NOT DEFINED CMAKE_INSTALL_NAME_TOOL)
   FIND_PROGRAM(CMAKE_INSTALL_NAME_TOOL install_name_tool)
   MARK_AS_ADVANCED(CMAKE_INSTALL_NAME_TOOL)
 ENDIF(NOT DEFINED CMAKE_INSTALL_NAME_TOOL)

 # Set the assumed (Pre 10.5 or Default) location of the developer tools
 SET(OSX_DEVELOPER_ROOT "/Developer")

 # Use the xcode-select tool if it's available (Xcode >= 3.0 installations)
 FIND_PROGRAM(CMAKE_XCODE_SELECT xcode-select)
 MARK_AS_ADVANCED(CMAKE_XCODE_SELECT)
 IF(CMAKE_XCODE_SELECT)
   EXECUTE_PROCESS(COMMAND ${CMAKE_XCODE_SELECT} "-print-path"
     OUTPUT_VARIABLE OSX_DEVELOPER_ROOT
     OUTPUT_STRIP_TRAILING_WHITESPACE)
 ENDIF(CMAKE_XCODE_SELECT)

 # Find installed SDKs
 # Start with Xcode-4.3+ default SDKs directory
 SET(_CMAKE_OSX_SDKS_DIR
   "${OSX_DEVELOPER_ROOT}/Platforms/MacOSX.platform/Developer/SDKs")
 FILE(GLOB _CMAKE_OSX_SDKS "${_CMAKE_OSX_SDKS_DIR}/*")

 # If not present, try pre-4.3 SDKs directory
 IF(NOT _CMAKE_OSX_SDKS)
 SET(_CMAKE_OSX_SDKS_DIR "${OSX_DEVELOPER_ROOT}/SDKs")
   FILE(GLOB _CMAKE_OSX_SDKS "${_CMAKE_OSX_SDKS_DIR}/*")
 ENDIF(NOT _CMAKE_OSX_SDKS)

 EXECUTE_PROCESS(COMMAND sw_vers -productVersion
   OUTPUT_VARIABLE CURRENT_OSX_VERSION
   OUTPUT_STRIP_TRAILING_WHITESPACE)

 #----------------------------------------------------------------------------
 # _CURRENT_OSX_VERSION - as a two-component string: 10.5, 10.6, ...
 #
 STRING(REGEX REPLACE "^([0-9]+\\.[0-9]+).*$" "\\1"
   _CURRENT_OSX_VERSION "${CURRENT_OSX_VERSION}")

 #----------------------------------------------------------------------------
 # CMAKE_OSX_DEPLOYMENT_TARGET

 # Set cache variable - end user may change this during ccmake or cmake-gui configure.
 IF(_CURRENT_OSX_VERSION VERSION_GREATER 10.3)
   SET(CMAKE_OSX_DEPLOYMENT_TARGET "$ENV{MACOSX_DEPLOYMENT_TARGET}" CACHE STRING
     "Minimum OS X version to target for deployment (at runtime); newer APIs weak linked. Set to empty string for default value.")
 ENDIF(_CURRENT_OSX_VERSION VERSION_GREATER 10.3)

 #----------------------------------------------------------------------------
 # CMAKE_OSX_SYSROOT

 # Environment variable set by the user overrides our default.
 # Use the same environment variable that Xcode uses.
 SET(ENV_SDKROOT "$ENV{SDKROOT}")

 # Set CMAKE_OSX_SYSROOT_DEFAULT based on _CURRENT_OSX_VERSION,
 # accounting for the known specially named SDKs.
 SET(CMAKE_OSX_SYSROOT_DEFAULT
   "${_CMAKE_OSX_SDKS_DIR}/MacOSX${_CURRENT_OSX_VERSION}.sdk")

 IF(_CURRENT_OSX_VERSION STREQUAL "10.4")
   SET(CMAKE_OSX_SYSROOT_DEFAULT
     "${_CMAKE_OSX_SDKS_DIR}/MacOSX10.4u.sdk")
 ENDIF(_CURRENT_OSX_VERSION STREQUAL "10.4")

 IF(_CURRENT_OSX_VERSION STREQUAL "10.3")
   SET(CMAKE_OSX_SYSROOT_DEFAULT
     "${_CMAKE_OSX_SDKS_DIR}/MacOSX10.3.9.sdk")
 ENDIF(_CURRENT_OSX_VERSION STREQUAL "10.3")

 # Use environment or default as initial cache value:
 IF(NOT ENV_SDKROOT STREQUAL "")
   SET(CMAKE_OSX_SYSROOT_VALUE ${ENV_SDKROOT})
 ELSE(NOT ENV_SDKROOT STREQUAL "")
   SET(CMAKE_OSX_SYSROOT_VALUE ${CMAKE_OSX_SYSROOT_DEFAULT})
 ENDIF(NOT ENV_SDKROOT STREQUAL "")

 # Set cache variable - end user may change this during ccmake or cmake-gui configure.
 SET(CMAKE_OSX_SYSROOT ${CMAKE_OSX_SYSROOT_VALUE} CACHE PATH
   "The product will be built against the headers and libraries located inside the indicated SDK.")

 #----------------------------------------------------------------------------
 function(SanityCheckSDKAndDeployTarget _sdk_path _deploy)
   if(_deploy STREQUAL "")
     return()
   endif()

   if(_sdk_path STREQUAL "")
     message(FATAL_ERROR "CMAKE_OSX_DEPLOYMENT_TARGET='${_deploy}' but CMAKE_OSX_SYSROOT is empty... - either set CMAKE_OSX_SYSROOT to a valid SDK or set CMAKE_OSX_DEPLOYMENT_TARGET to empty")
   endif()

   string(REGEX REPLACE "(.*MacOSX*)(....)(.*\\.sdk)" "\\2" SDK "${_sdk_path}")
   if(_deploy GREATER "${SDK}")
     message(FATAL_ERROR "CMAKE_OSX_DEPLOYMENT_TARGET (${_deploy}) is greater than CMAKE_OSX_SYSROOT SDK (${_sdk_path}). Please set CMAKE_OSX_DEPLOYMENT_TARGET to ${SDK} or lower")
   endif()
 endfunction(SanityCheckSDKAndDeployTarget)
 #----------------------------------------------------------------------------

 # Make sure the combination of SDK and Deployment Target are allowed
 SanityCheckSDKAndDeployTarget("${CMAKE_OSX_SYSROOT}" "${CMAKE_OSX_DEPLOYMENT_TARGET}")

 # set _CMAKE_OSX_MACHINE to uname -m
 EXECUTE_PROCESS(COMMAND uname -m
   OUTPUT_STRIP_TRAILING_WHITESPACE
   OUTPUT_VARIABLE _CMAKE_OSX_MACHINE)

 # check for Power PC and change to ppc
 IF(_CMAKE_OSX_MACHINE MATCHES "Power")
   SET(_CMAKE_OSX_MACHINE ppc)
 ENDIF(_CMAKE_OSX_MACHINE MATCHES "Power")

 # check for environment variable CMAKE_OSX_ARCHITECTURES
 # if it is set.
 IF(NOT "$ENV{CMAKE_OSX_ARCHITECTURES}" STREQUAL "")
   SET(CMAKE_OSX_ARCHITECTURES_VALUE "$ENV{CMAKE_OSX_ARCHITECTURES}")
 ELSE(NOT "$ENV{CMAKE_OSX_ARCHITECTURES}" STREQUAL "")
   SET(CMAKE_OSX_ARCHITECTURES_VALUE "")
 ENDIF(NOT "$ENV{CMAKE_OSX_ARCHITECTURES}" STREQUAL "")

 # now put _CMAKE_OSX_MACHINE into the cache
 SET(CMAKE_OSX_ARCHITECTURES ${CMAKE_OSX_ARCHITECTURES_VALUE} CACHE STRING
   "Build architectures for OSX")


 IF("${CMAKE_BACKWARDS_COMPATIBILITY}" MATCHES "^1\\.[0-6]$")
   SET(CMAKE_SHARED_MODULE_CREATE_C_FLAGS
     "${CMAKE_SHARED_MODULE_CREATE_C_FLAGS} -flat_namespace -undefined suppress")
 ENDIF("${CMAKE_BACKWARDS_COMPATIBILITY}" MATCHES "^1\\.[0-6]$")

 IF(NOT XCODE)
   # Enable shared library versioning.  This flag is not actually referenced
   # but the fact that the setting exists will cause the generators to support
   # soname computation.
   SET(CMAKE_SHARED_LIBRARY_SONAME_C_FLAG "-install_name")
 ENDIF(NOT XCODE)

 # Xcode does not support -isystem yet.
 IF(XCODE)
   SET(CMAKE_INCLUDE_SYSTEM_FLAG_C)
   SET(CMAKE_INCLUDE_SYSTEM_FLAG_CXX)
 ENDIF(XCODE)

 IF("${_CURRENT_OSX_VERSION}" VERSION_LESS "10.5")
   # Need to list dependent shared libraries on link line.  When building
   # with -isysroot (for universal binaries), the linker always looks for
   # dependent libraries under the sysroot.  Listing them on the link
   # line works around the problem.
   SET(CMAKE_LINK_DEPENDENT_LIBRARY_FILES 1)
 ENDIF()

 SET(CMAKE_C_CREATE_SHARED_LIBRARY_FORBIDDEN_FLAGS -w)
 SET(CMAKE_CXX_CREATE_SHARED_LIBRARY_FORBIDDEN_FLAGS -w)
 SET(CMAKE_C_CREATE_SHARED_LIBRARY
   "<CMAKE_C_COMPILER> <LANGUAGE_COMPILE_FLAGS> <CMAKE_SHARED_LIBRARY_CREATE_C_FLAGS> <LINK_FLAGS> -o <TARGET> -install_name <TARGET_INSTALLNAME_DIR><TARGET_SONAME> <OBJECTS> <LINK_LIBRARIES>")
 SET(CMAKE_CXX_CREATE_SHARED_LIBRARY
   "<CMAKE_CXX_COMPILER> <LANGUAGE_COMPILE_FLAGS> <CMAKE_SHARED_LIBRARY_CREATE_CXX_FLAGS> <LINK_FLAGS> -o <TARGET> -install_name <TARGET_INSTALLNAME_DIR><TARGET_SONAME> <OBJECTS> <LINK_LIBRARIES>")
 SET(CMAKE_Fortran_CREATE_SHARED_LIBRARY
   "<CMAKE_Fortran_COMPILER> <LANGUAGE_COMPILE_FLAGS> <CMAKE_SHARED_LIBRARY_CREATE_Fortran_FLAGS> <LINK_FLAGS> -o <TARGET> -install_name <TARGET_INSTALLNAME_DIR><TARGET_SONAME> <OBJECTS> <LINK_LIBRARIES>")

 SET(CMAKE_CXX_CREATE_SHARED_MODULE
       "<CMAKE_CXX_COMPILER> <LANGUAGE_COMPILE_FLAGS> <CMAKE_SHARED_MODULE_CREATE_CXX_FLAGS> <LINK_FLAGS> -o <TARGET> <OBJECTS> <LINK_LIBRARIES>")

 SET(CMAKE_C_CREATE_SHARED_MODULE
       "<CMAKE_C_COMPILER>  <LANGUAGE_COMPILE_FLAGS> <CMAKE_SHARED_MODULE_CREATE_C_FLAGS> <LINK_FLAGS> -o <TARGET> <OBJECTS> <LINK_LIBRARIES>")

 SET(CMAKE_Fortran_CREATE_SHARED_MODULE
       "<CMAKE_Fortran_COMPILER>  <LANGUAGE_COMPILE_FLAGS> <CMAKE_SHARED_MODULE_CREATE_Fortran_FLAGS> <LINK_FLAGS> -o <TARGET> <OBJECTS> <LINK_LIBRARIES>")

 SET(CMAKE_C_CREATE_MACOSX_FRAMEWORK
       "<CMAKE_C_COMPILER> <LANGUAGE_COMPILE_FLAGS> <CMAKE_SHARED_LIBRARY_CREATE_C_FLAGS> <LINK_FLAGS> -o <TARGET> -install_name <TARGET_INSTALLNAME_DIR><TARGET_SONAME> <OBJECTS> <LINK_LIBRARIES>")
 SET(CMAKE_CXX_CREATE_MACOSX_FRAMEWORK
       "<CMAKE_CXX_COMPILER> <LANGUAGE_COMPILE_FLAGS> <CMAKE_SHARED_LIBRARY_CREATE_CXX_FLAGS> <LINK_FLAGS> -o <TARGET> -install_name <TARGET_INSTALLNAME_DIR><TARGET_SONAME> <OBJECTS> <LINK_LIBRARIES>")


 # default to searching for frameworks first
 SET(CMAKE_FIND_FRAMEWORK FIRST)
 # set up the default search directories for frameworks
 SET(CMAKE_SYSTEM_FRAMEWORK_PATH
   ~/Library/Frameworks
   /Library/Frameworks
   /Network/Library/Frameworks
   /System/Library/Frameworks)

 # default to searching for application bundles first
 SET(CMAKE_FIND_APPBUNDLE FIRST)
 # set up the default search directories for application bundles
 SET(_apps_paths)
 FOREACH(_path
   "~/Applications"
   "/Applications"
   "${OSX_DEVELOPER_ROOT}/../Applications" # Xcode 4.3+
   "${OSX_DEVELOPER_ROOT}/Applications"    # pre-4.3
   )
   GET_FILENAME_COMPONENT(_apps "${_path}" ABSOLUTE)
   IF(EXISTS "${_apps}")
     LIST(APPEND _apps_paths "${_apps}")
   ENDIF()
 ENDFOREACH()
 LIST(REMOVE_DUPLICATES _apps_paths)
 SET(CMAKE_SYSTEM_APPBUNDLE_PATH
   ${_apps_paths})
 UNSET(_apps_paths)

 INCLUDE(Platform/UnixPaths)
 LIST(APPEND CMAKE_SYSTEM_PREFIX_PATH
   /sw        # Fink
   /opt/local # MacPorts
   )
	SET(APPLE 1)

	# Darwin versions:
	# 6.x == Mac OSX 10.2 (Jaguar)
	# 7.x == Mac OSX 10.3 (Panther)
	# 8.x == Mac OSX 10.4 (Tiger)
	# 9.x == Mac OSX 10.5 (Leopard)
	# 10.x == Mac OSX 10.6 (Snow Leopard)
	# 11.x == Mac OSX 10.7 (Lion)
	# 12.x == Mac OSX 10.8 (Mountain Lion)
	STRING(REGEX REPLACE "^([0-9]+)\\.([0-9]+).*$" "\\1" DARWIN_MAJOR_VERSION "${CMAKE_SYSTEM_VERSION}")
	STRING(REGEX REPLACE "^([0-9]+)\\.([0-9]+).*$" "\\2" DARWIN_MINOR_VERSION "${CMAKE_SYSTEM_VERSION}")

	# Do not use the "-Wl,-search_paths_first" flag with the OSX 10.2 compiler.
	# Done this way because it is too early to do a TRY_COMPILE.
	IF(NOT DEFINED HAVE_FLAG_SEARCH_PATHS_FIRST)
	SET(HAVE_FLAG_SEARCH_PATHS_FIRST 0)
	IF("${DARWIN_MAJOR_VERSION}" GREATER 6)
	SET(HAVE_FLAG_SEARCH_PATHS_FIRST 1)
	ENDIF("${DARWIN_MAJOR_VERSION}" GREATER 6)
	ENDIF(NOT DEFINED HAVE_FLAG_SEARCH_PATHS_FIRST)
	# More desirable, but does not work:
	#INCLUDE(CheckCXXCompilerFlag)
	#CHECK_CXX_COMPILER_FLAG("-Wl,-search_paths_first" HAVE_FLAG_SEARCH_PATHS_FIRST)

	SET(CMAKE_SHARED_LIBRARY_PREFIX "lib")
	SET(CMAKE_SHARED_LIBRARY_SUFFIX ".dylib")
	SET(CMAKE_SHARED_MODULE_PREFIX "lib")
	SET(CMAKE_SHARED_MODULE_SUFFIX ".so")
	SET(CMAKE_MODULE_EXISTS 1)
	SET(CMAKE_DL_LIBS "")

	SET(CMAKE_C_OSX_COMPATIBILITY_VERSION_FLAG "-compatibility_version ")
	SET(CMAKE_C_OSX_CURRENT_VERSION_FLAG "-current_version ")
	SET(CMAKE_CXX_OSX_COMPATIBILITY_VERSION_FLAG "${CMAKE_C_OSX_COMPATIBILITY_VERSION_FLAG}")
	SET(CMAKE_CXX_OSX_CURRENT_VERSION_FLAG "${CMAKE_C_OSX_CURRENT_VERSION_FLAG}")

	SET(CMAKE_C_LINK_FLAGS "-Wl,-headerpad_max_install_names")
	SET(CMAKE_CXX_LINK_FLAGS "-Wl,-headerpad_max_install_names")

	IF(HAVE_FLAG_SEARCH_PATHS_FIRST)
	SET(CMAKE_C_LINK_FLAGS "-Wl,-search_paths_first ${CMAKE_C_LINK_FLAGS}")
	SET(CMAKE_CXX_LINK_FLAGS "-Wl,-search_paths_first ${CMAKE_CXX_LINK_FLAGS}")
	ENDIF(HAVE_FLAG_SEARCH_PATHS_FIRST)

	SET(CMAKE_PLATFORM_HAS_INSTALLNAME 1)
	SET(CMAKE_SHARED_LIBRARY_CREATE_C_FLAGS "-dynamiclib -Wl,-headerpad_max_install_names")
	SET(CMAKE_SHARED_MODULE_CREATE_C_FLAGS "-bundle -Wl,-headerpad_max_install_names")
	SET(CMAKE_SHARED_MODULE_LOADER_C_FLAG "-Wl,-bundle_loader,")
	SET(CMAKE_SHARED_MODULE_LOADER_CXX_FLAG "-Wl,-bundle_loader,")
	SET(CMAKE_FIND_LIBRARY_SUFFIXES ".dylib" ".so" ".a")

	# hack: if a new cmake (which uses CMAKE_INSTALL_NAME_TOOL) runs on an old build tree
	# (where install_name_tool was hardcoded) and where CMAKE_INSTALL_NAME_TOOL isn't in the cache
	# and still cmake didn't fail in CMakeFindBinUtils.cmake (because it isn't rerun)
	# hardcode CMAKE_INSTALL_NAME_TOOL here to install_name_tool, so it behaves as it did before, Alex
	IF(NOT DEFINED CMAKE_INSTALL_NAME_TOOL)
	FIND_PROGRAM(CMAKE_INSTALL_NAME_TOOL install_name_tool)
	MARK_AS_ADVANCED(CMAKE_INSTALL_NAME_TOOL)
	ENDIF(NOT DEFINED CMAKE_INSTALL_NAME_TOOL)

	# Set the assumed (Pre 10.5 or Default) location of the developer tools
	SET(OSX_DEVELOPER_ROOT "/Developer")

	# Use the xcode-select tool if it's available (Xcode >= 3.0 installations)
	FIND_PROGRAM(CMAKE_XCODE_SELECT xcode-select)
	MARK_AS_ADVANCED(CMAKE_XCODE_SELECT)
	IF(CMAKE_XCODE_SELECT)
	EXECUTE_PROCESS(COMMAND ${CMAKE_XCODE_SELECT} "-print-path"
	OUTPUT_VARIABLE OSX_DEVELOPER_ROOT
	OUTPUT_STRIP_TRAILING_WHITESPACE)
	ENDIF(CMAKE_XCODE_SELECT)

	# Find installed SDKs
	# Start with Xcode-4.3+ default SDKs directory
	SET(_CMAKE_OSX_SDKS_DIR
	"${OSX_DEVELOPER_ROOT}/Platforms/MacOSX.platform/Developer/SDKs")
	FILE(GLOB _CMAKE_OSX_SDKS "${_CMAKE_OSX_SDKS_DIR}/*")

	# If not present, try pre-4.3 SDKs directory
	IF(NOT _CMAKE_OSX_SDKS)
	SET(_CMAKE_OSX_SDKS_DIR "${OSX_DEVELOPER_ROOT}/SDKs")
	FILE(GLOB _CMAKE_OSX_SDKS "${_CMAKE_OSX_SDKS_DIR}/*")
	ENDIF(NOT _CMAKE_OSX_SDKS)

	EXECUTE_PROCESS(COMMAND sw_vers -productVersion
	OUTPUT_VARIABLE CURRENT_OSX_VERSION
	OUTPUT_STRIP_TRAILING_WHITESPACE)

	#----------------------------------------------------------------------------
	# _CURRENT_OSX_VERSION - as a two-component string: 10.5, 10.6, ...
	#
	STRING(REGEX REPLACE "^([0-9]+\\.[0-9]+).*$" "\\1"
	_CURRENT_OSX_VERSION "${CURRENT_OSX_VERSION}")

	#----------------------------------------------------------------------------
	# CMAKE_OSX_DEPLOYMENT_TARGET

	# Set cache variable - end user may change this during ccmake or cmake-gui configure.
	IF(_CURRENT_OSX_VERSION VERSION_GREATER 10.3)
	SET(CMAKE_OSX_DEPLOYMENT_TARGET "$ENV{MACOSX_DEPLOYMENT_TARGET}" CACHE STRING
	"Minimum OS X version to target for deployment (at runtime); newer APIs weak linked. Set to empty string for default value.")
	ENDIF(_CURRENT_OSX_VERSION VERSION_GREATER 10.3)

	#----------------------------------------------------------------------------
	# CMAKE_OSX_SYSROOT

	# Environment variable set by the user overrides our default.
	# Use the same environment variable that Xcode uses.
	SET(ENV_SDKROOT "$ENV{SDKROOT}")

	# Set CMAKE_OSX_SYSROOT_DEFAULT based on _CURRENT_OSX_VERSION,
	# accounting for the known specially named SDKs.
	SET(CMAKE_OSX_SYSROOT_DEFAULT
	"${_CMAKE_OSX_SDKS_DIR}/MacOSX${_CURRENT_OSX_VERSION}.sdk")

	IF(_CURRENT_OSX_VERSION STREQUAL "10.4")
	SET(CMAKE_OSX_SYSROOT_DEFAULT
	"${_CMAKE_OSX_SDKS_DIR}/MacOSX10.4u.sdk")
	ENDIF(_CURRENT_OSX_VERSION STREQUAL "10.4")

	IF(_CURRENT_OSX_VERSION STREQUAL "10.3")
	SET(CMAKE_OSX_SYSROOT_DEFAULT
	"${_CMAKE_OSX_SDKS_DIR}/MacOSX10.3.9.sdk")
	ENDIF(_CURRENT_OSX_VERSION STREQUAL "10.3")

	# Use environment or default as initial cache value:
	IF(NOT ENV_SDKROOT STREQUAL "")
	SET(CMAKE_OSX_SYSROOT_VALUE ${ENV_SDKROOT})
	ELSE(NOT ENV_SDKROOT STREQUAL "")
	SET(CMAKE_OSX_SYSROOT_VALUE ${CMAKE_OSX_SYSROOT_DEFAULT})
	ENDIF(NOT ENV_SDKROOT STREQUAL "")

	# Set cache variable - end user may change this during ccmake or cmake-gui configure.
	SET(CMAKE_OSX_SYSROOT ${CMAKE_OSX_SYSROOT_VALUE} CACHE PATH
	"The product will be built against the headers and libraries located inside the indicated SDK.")

	#----------------------------------------------------------------------------
	function(SanityCheckSDKAndDeployTarget _sdk_path _deploy)
	if(_deploy STREQUAL "")
	return()
	endif()

	if(_sdk_path STREQUAL "")
	message(FATAL_ERROR "CMAKE_OSX_DEPLOYMENT_TARGET='${_deploy}' but CMAKE_OSX_SYSROOT is empty... - either set CMAKE_OSX_SYSROOT to a valid SDK or set CMAKE_OSX_DEPLOYMENT_TARGET to empty")
	endif()

	string(REGEX REPLACE "(.MacOSX)(....)(.*\\.sdk)" "\\2" SDK "${_sdk_path}")
	if(_deploy GREATER "${SDK}")
	message(FATAL_ERROR "CMAKE_OSX_DEPLOYMENT_TARGET (${_deploy}) is greater than CMAKE_OSX_SYSROOT SDK (${_sdk_path}). Please set CMAKE_OSX_DEPLOYMENT_TARGET to ${SDK} or lower")
	endif()
	endfunction(SanityCheckSDKAndDeployTarget)
	#----------------------------------------------------------------------------

	# Make sure the combination of SDK and Deployment Target are allowed
	SanityCheckSDKAndDeployTarget("${CMAKE_OSX_SYSROOT}" "${CMAKE_OSX_DEPLOYMENT_TARGET}")

	# set _CMAKE_OSX_MACHINE to uname -m
	EXECUTE_PROCESS(COMMAND uname -m
	OUTPUT_STRIP_TRAILING_WHITESPACE
	OUTPUT_VARIABLE _CMAKE_OSX_MACHINE)

	# check for Power PC and change to ppc
	IF(_CMAKE_OSX_MACHINE MATCHES "Power")
	SET(_CMAKE_OSX_MACHINE ppc)
	ENDIF(_CMAKE_OSX_MACHINE MATCHES "Power")

	# check for environment variable CMAKE_OSX_ARCHITECTURES
	# if it is set.
	IF(NOT "$ENV{CMAKE_OSX_ARCHITECTURES}" STREQUAL "")
	SET(CMAKE_OSX_ARCHITECTURES_VALUE "$ENV{CMAKE_OSX_ARCHITECTURES}")
	ELSE(NOT "$ENV{CMAKE_OSX_ARCHITECTURES}" STREQUAL "")
	SET(CMAKE_OSX_ARCHITECTURES_VALUE "")
	ENDIF(NOT "$ENV{CMAKE_OSX_ARCHITECTURES}" STREQUAL "")

	# now put _CMAKE_OSX_MACHINE into the cache
	SET(CMAKE_OSX_ARCHITECTURES ${CMAKE_OSX_ARCHITECTURES_VALUE} CACHE STRING
	"Build architectures for OSX")


	IF("${CMAKE_BACKWARDS_COMPATIBILITY}" MATCHES "^1\\.[0-6]$")
	SET(CMAKE_SHARED_MODULE_CREATE_C_FLAGS
	"${CMAKE_SHARED_MODULE_CREATE_C_FLAGS} -flat_namespace -undefined suppress")
	ENDIF("${CMAKE_BACKWARDS_COMPATIBILITY}" MATCHES "^1\\.[0-6]$")

	IF(NOT XCODE)
	# Enable shared library versioning. This flag is not actually referenced
	# but the fact that the setting exists will cause the generators to support
	# soname computation.
	SET(CMAKE_SHARED_LIBRARY_SONAME_C_FLAG "-install_name")
	ENDIF(NOT XCODE)

	# Xcode does not support -isystem yet.
	IF(XCODE)
	SET(CMAKE_INCLUDE_SYSTEM_FLAG_C)
	SET(CMAKE_INCLUDE_SYSTEM_FLAG_CXX)
	ENDIF(XCODE)

	IF("${_CURRENT_OSX_VERSION}" VERSION_LESS "10.5")
	# Need to list dependent shared libraries on link line. When building
	# with -isysroot (for universal binaries), the linker always looks for
	# dependent libraries under the sysroot. Listing them on the link
	# line works around the problem.
	SET(CMAKE_LINK_DEPENDENT_LIBRARY_FILES 1)
	ENDIF()

	SET(CMAKE_C_CREATE_SHARED_LIBRARY_FORBIDDEN_FLAGS -w)
	SET(CMAKE_CXX_CREATE_SHARED_LIBRARY_FORBIDDEN_FLAGS -w)
	SET(CMAKE_C_CREATE_SHARED_LIBRARY
	"<CMAKE_C_COMPILER> <LANGUAGE_COMPILE_FLAGS> <CMAKE_SHARED_LIBRARY_CREATE_C_FLAGS> <LINK_FLAGS> -o <TARGET> -install_name <TARGET_INSTALLNAME_DIR><TARGET_SONAME> <OBJECTS> <LINK_LIBRARIES>")
	SET(CMAKE_CXX_CREATE_SHARED_LIBRARY
	"<CMAKE_CXX_COMPILER> <LANGUAGE_COMPILE_FLAGS> <CMAKE_SHARED_LIBRARY_CREATE_CXX_FLAGS> <LINK_FLAGS> -o <TARGET> -install_name <TARGET_INSTALLNAME_DIR><TARGET_SONAME> <OBJECTS> <LINK_LIBRARIES>")
	SET(CMAKE_Fortran_CREATE_SHARED_LIBRARY
	"<CMAKE_Fortran_COMPILER> <LANGUAGE_COMPILE_FLAGS> <CMAKE_SHARED_LIBRARY_CREATE_Fortran_FLAGS> <LINK_FLAGS> -o <TARGET> -install_name <TARGET_INSTALLNAME_DIR><TARGET_SONAME> <OBJECTS> <LINK_LIBRARIES>")

	SET(CMAKE_CXX_CREATE_SHARED_MODULE
	"<CMAKE_CXX_COMPILER> <LANGUAGE_COMPILE_FLAGS> <CMAKE_SHARED_MODULE_CREATE_CXX_FLAGS> <LINK_FLAGS> -o <TARGET> <OBJECTS> <LINK_LIBRARIES>")

	SET(CMAKE_C_CREATE_SHARED_MODULE
	"<CMAKE_C_COMPILER> <LANGUAGE_COMPILE_FLAGS> <CMAKE_SHARED_MODULE_CREATE_C_FLAGS> <LINK_FLAGS> -o <TARGET> <OBJECTS> <LINK_LIBRARIES>")

	SET(CMAKE_Fortran_CREATE_SHARED_MODULE
	"<CMAKE_Fortran_COMPILER> <LANGUAGE_COMPILE_FLAGS> <CMAKE_SHARED_MODULE_CREATE_Fortran_FLAGS> <LINK_FLAGS> -o <TARGET> <OBJECTS> <LINK_LIBRARIES>")

	SET(CMAKE_C_CREATE_MACOSX_FRAMEWORK
	"<CMAKE_C_COMPILER> <LANGUAGE_COMPILE_FLAGS> <CMAKE_SHARED_LIBRARY_CREATE_C_FLAGS> <LINK_FLAGS> -o <TARGET> -install_name <TARGET_INSTALLNAME_DIR><TARGET_SONAME> <OBJECTS> <LINK_LIBRARIES>")
	SET(CMAKE_CXX_CREATE_MACOSX_FRAMEWORK
	"<CMAKE_CXX_COMPILER> <LANGUAGE_COMPILE_FLAGS> <CMAKE_SHARED_LIBRARY_CREATE_CXX_FLAGS> <LINK_FLAGS> -o <TARGET> -install_name <TARGET_INSTALLNAME_DIR><TARGET_SONAME> <OBJECTS> <LINK_LIBRARIES>")



	# default to searching for frameworks first
	SET(CMAKE_FIND_FRAMEWORK FIRST)
	# set up the default search directories for frameworks
	SET(CMAKE_SYSTEM_FRAMEWORK_PATH
	~/Library/Frameworks
	/Library/Frameworks
	/Network/Library/Frameworks
	/System/Library/Frameworks)

	# default to searching for application bundles first
	SET(CMAKE_FIND_APPBUNDLE FIRST)
	# set up the default search directories for application bundles
	SET(_apps_paths)
	FOREACH(_path
	"~/Applications"
	"/Applications"
	"${OSX_DEVELOPER_ROOT}/../Applications" # Xcode 4.3+
	"${OSX_DEVELOPER_ROOT}/Applications" # pre-4.3
	)
	GET_FILENAME_COMPONENT(_apps "${_path}" ABSOLUTE)
	IF(EXISTS "${_apps}")
	LIST(APPEND _apps_paths "${_apps}")
	ENDIF()
	ENDFOREACH()
	LIST(REMOVE_DUPLICATES _apps_paths)
	SET(CMAKE_SYSTEM_APPBUNDLE_PATH
	${_apps_paths})
	UNSET(_apps_paths)

	INCLUDE(Platform/UnixPaths)
	LIST(APPEND CMAKE_SYSTEM_PREFIX_PATH
	/sw # Fink
	/opt/local # MacPorts
	)