OS X: Factor a Darwin-Initialize module out of Platform/Darwin

Initialize variables CMAKE_OSX_SYSROOT, CMAKE_OSX_DEPLOYMENT_TARGET, and
CMAKE_OSX_ARCHITECTURES prior to enabling any languages.  This will
allow compiler identification to consider these values.

Modules/Platform/Darwin-Initialize.cmake

@@ -0,0 +1,136 @@
+# Ask xcode-select where to find /Developer or fall back to ancient location.
+execute_process(COMMAND xcode-select -print-path
+  OUTPUT_VARIABLE _stdout
+  OUTPUT_STRIP_TRAILING_WHITESPACE
+  ERROR_VARIABLE _stderr
+  RESULT_VARIABLE _failed)
+if(NOT _failed AND IS_DIRECTORY ${_stdout})
+  set(OSX_DEVELOPER_ROOT ${_stdout})
+elseif(IS_DIRECTORY "/Developer")
+  set(OSX_DEVELOPER_ROOT "/Developer")
+else()
+  set(OSX_DEVELOPER_ROOT "")
+endif()
+
+execute_process(COMMAND sw_vers -productVersion
+  OUTPUT_VARIABLE CURRENT_OSX_VERSION
+  OUTPUT_STRIP_TRAILING_WHITESPACE)
+
+# Save CMAKE_OSX_ARCHITECTURES from the environment.
+set(CMAKE_OSX_ARCHITECTURES "$ENV{CMAKE_OSX_ARCHITECTURES}" CACHE STRING
+  "Build architectures for OSX")
+
+#----------------------------------------------------------------------------
+# _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 "$ENV{MACOSX_DEPLOYMENT_TARGET}" CACHE STRING
+    "Minimum OS X version to target for deployment (at runtime); newer APIs weak linked. Set to empty string for default value.")
+endif()
+
+#----------------------------------------------------------------------------
+# CMAKE_OSX_SYSROOT
+
+if(CMAKE_OSX_SYSROOT)
+  # Use the existing value without further computation to choose a default.
+  set(_CMAKE_OSX_SYSROOT_DEFAULT "${CMAKE_OSX_SYSROOT}")
+elseif(NOT "x$ENV{SDKROOT}" STREQUAL "x" AND
+        (NOT "x$ENV{SDKROOT}" MATCHES "/" OR IS_DIRECTORY "$ENV{SDKROOT}"))
+  # Use the value of SDKROOT from the environment.
+  set(_CMAKE_OSX_SYSROOT_DEFAULT "$ENV{SDKROOT}")
+elseif("${CMAKE_GENERATOR}" MATCHES Xcode
+       OR CMAKE_OSX_DEPLOYMENT_TARGET
+       OR CMAKE_OSX_ARCHITECTURES MATCHES "[^;]"
+       OR NOT EXISTS "/usr/include/sys/types.h")
+  # Find installed SDKs in either Xcode-4.3+ or pre-4.3 SDKs directory.
+  set(_CMAKE_OSX_SDKS_DIR "")
+  if(OSX_DEVELOPER_ROOT)
+    foreach(d Platforms/MacOSX.platform/Developer/SDKs SDKs)
+      file(GLOB _CMAKE_OSX_SDKS ${OSX_DEVELOPER_ROOT}/${d}/*)
+      if(_CMAKE_OSX_SDKS)
+        set(_CMAKE_OSX_SDKS_DIR ${OSX_DEVELOPER_ROOT}/${d})
+        break()
+      endif()
+    endforeach()
+  endif()
+
+  if(_CMAKE_OSX_SDKS_DIR)
+    # Select SDK for current OSX version accounting for the known
+    # specially named SDKs.
+    set(_CMAKE_OSX_SDKS_VER_SUFFIX_10.4 "u")
+    set(_CMAKE_OSX_SDKS_VER_SUFFIX_10.3 ".9")
+    if(CMAKE_OSX_DEPLOYMENT_TARGET)
+      set(_CMAKE_OSX_SDKS_VER ${CMAKE_OSX_DEPLOYMENT_TARGET}${_CMAKE_OSX_SDKS_VER_SUFFIX_${CMAKE_OSX_DEPLOYMENT_TARGET}})
+      set(_CMAKE_OSX_SYSROOT_CHECK "${_CMAKE_OSX_SDKS_DIR}/MacOSX${_CMAKE_OSX_SDKS_VER}.sdk")
+      if(IS_DIRECTORY "${_CMAKE_OSX_SYSROOT_CHECK}")
+        set(_CMAKE_OSX_SYSROOT_DEFAULT "${_CMAKE_OSX_SYSROOT_CHECK}")
+      else()
+        set(_CMAKE_OSX_SDKS_VER ${_CURRENT_OSX_VERSION}${_CMAKE_OSX_SDKS_VER_SUFFIX_${_CURRENT_OSX_VERSION}})
+        set(_CMAKE_OSX_SYSROOT_DEFAULT "${_CMAKE_OSX_SDKS_DIR}/MacOSX${_CMAKE_OSX_SDKS_VER}.sdk")
+        message(WARNING
+          "CMAKE_OSX_DEPLOYMENT_TARGET is '${CMAKE_OSX_DEPLOYMENT_TARGET}' "
+          "but the matching SDK does not exist at:\n \"${_CMAKE_OSX_SYSROOT_CHECK}\"\n"
+          "Instead using SDK:\n \"${_CMAKE_OSX_SYSROOT_DEFAULT}\"\n"
+          "matching the host OS X version."
+          )
+      endif()
+    else()
+      set(_CMAKE_OSX_SDKS_VER ${_CURRENT_OSX_VERSION}${_CMAKE_OSX_SDKS_VER_SUFFIX_${_CURRENT_OSX_VERSION}})
+      set(_CMAKE_OSX_SYSROOT_DEFAULT "${_CMAKE_OSX_SDKS_DIR}/MacOSX${_CMAKE_OSX_SDKS_VER}.sdk")
+    endif()
+  else()
+    # Assume developer files are in root (such as Xcode 4.5 command-line tools).
+    set(_CMAKE_OSX_SYSROOT_DEFAULT "")
+  endif()
+endif()
+
+# Set cache variable - end user may change this during ccmake or cmake-gui configure.
+# Choose the type based on the current value.
+set(_CMAKE_OSX_SYSROOT_TYPE STRING)
+foreach(v CMAKE_OSX_SYSROOT _CMAKE_OSX_SYSROOT_DEFAULT)
+  if("x${${v}}" MATCHES "/")
+    set(_CMAKE_OSX_SYSROOT_TYPE PATH)
+    break()
+  endif()
+endforeach()
+set(CMAKE_OSX_SYSROOT "${_CMAKE_OSX_SYSROOT_DEFAULT}" CACHE ${_CMAKE_OSX_SYSROOT_TYPE}
+  "The product will be built against the headers and libraries located inside the indicated SDK.")
+
+# Transform the cached value to something we can use.
+set(_CMAKE_OSX_SYSROOT_ORIG "${CMAKE_OSX_SYSROOT}")
+set(_CMAKE_OSX_SYSROOT_PATH "")
+if(CMAKE_OSX_SYSROOT)
+  if("x${CMAKE_OSX_SYSROOT}" MATCHES "/")
+    # This is a path to the SDK.  Make sure it exists.
+    if(NOT IS_DIRECTORY "${CMAKE_OSX_SYSROOT}")
+      message(WARNING "Ignoring CMAKE_OSX_SYSROOT value:\n ${CMAKE_OSX_SYSROOT}\n"
+        "because the directory does not exist.")
+      set(CMAKE_OSX_SYSROOT "")
+      set(_CMAKE_OSX_SYSROOT_ORIG "")
+    endif()
+    set(_CMAKE_OSX_SYSROOT_PATH "${CMAKE_OSX_SYSROOT}")
+  else()
+    # Transform the sdk name into a path.
+    execute_process(
+      COMMAND xcodebuild -sdk ${CMAKE_OSX_SYSROOT} -version Path
+      OUTPUT_VARIABLE _stdout
+      OUTPUT_STRIP_TRAILING_WHITESPACE
+      ERROR_VARIABLE _stderr
+      RESULT_VARIABLE _failed
+      )
+    if(NOT _failed AND IS_DIRECTORY "${_stdout}")
+      set(_CMAKE_OSX_SYSROOT_PATH "${_stdout}")
+      # For non-Xcode generators use the path.
+      if(NOT "${CMAKE_GENERATOR}" MATCHES "Xcode")
+        set(CMAKE_OSX_SYSROOT "${_CMAKE_OSX_SYSROOT_PATH}")
+      endif()
+    endif()
+  endif()
+endif()

Modules/Platform/Darwin.cmake

@@ -64,143 +64,6 @@ if(NOT DEFINED CMAKE_INSTALL_NAME_TOOL)
   mark_as_advanced(CMAKE_INSTALL_NAME_TOOL)
 endif()
 
-# Ask xcode-select where to find /Developer or fall back to ancient location.
-execute_process(COMMAND xcode-select -print-path
-  OUTPUT_VARIABLE _stdout
-  OUTPUT_STRIP_TRAILING_WHITESPACE
-  ERROR_VARIABLE _stderr
-  RESULT_VARIABLE _failed)
-if(NOT _failed AND IS_DIRECTORY ${_stdout})
-  set(OSX_DEVELOPER_ROOT ${_stdout})
-elseif(IS_DIRECTORY "/Developer")
-  set(OSX_DEVELOPER_ROOT "/Developer")
-else()
-  set(OSX_DEVELOPER_ROOT "")
-endif()
-
-execute_process(COMMAND sw_vers -productVersion
-  OUTPUT_VARIABLE CURRENT_OSX_VERSION
-  OUTPUT_STRIP_TRAILING_WHITESPACE)
-
-# Save CMAKE_OSX_ARCHITECTURES from the environment.
-set(CMAKE_OSX_ARCHITECTURES "$ENV{CMAKE_OSX_ARCHITECTURES}" CACHE STRING
-  "Build architectures for OSX")
-
-#----------------------------------------------------------------------------
-# _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 "$ENV{MACOSX_DEPLOYMENT_TARGET}" CACHE STRING
-    "Minimum OS X version to target for deployment (at runtime); newer APIs weak linked. Set to empty string for default value.")
-endif()
-
-#----------------------------------------------------------------------------
-# CMAKE_OSX_SYSROOT
-
-if(CMAKE_OSX_SYSROOT)
-  # Use the existing value without further computation to choose a default.
-  set(_CMAKE_OSX_SYSROOT_DEFAULT "${CMAKE_OSX_SYSROOT}")
-elseif(NOT "x$ENV{SDKROOT}" STREQUAL "x" AND
-        (NOT "x$ENV{SDKROOT}" MATCHES "/" OR IS_DIRECTORY "$ENV{SDKROOT}"))
-  # Use the value of SDKROOT from the environment.
-  set(_CMAKE_OSX_SYSROOT_DEFAULT "$ENV{SDKROOT}")
-elseif("${CMAKE_GENERATOR}" MATCHES Xcode
-       OR CMAKE_OSX_DEPLOYMENT_TARGET
-       OR CMAKE_OSX_ARCHITECTURES MATCHES "[^;]"
-       OR NOT EXISTS "/usr/include/sys/types.h")
-  # Find installed SDKs in either Xcode-4.3+ or pre-4.3 SDKs directory.
-  set(_CMAKE_OSX_SDKS_DIR "")
-  if(OSX_DEVELOPER_ROOT)
-    foreach(d Platforms/MacOSX.platform/Developer/SDKs SDKs)
-      file(GLOB _CMAKE_OSX_SDKS ${OSX_DEVELOPER_ROOT}/${d}/*)
-      if(_CMAKE_OSX_SDKS)
-        set(_CMAKE_OSX_SDKS_DIR ${OSX_DEVELOPER_ROOT}/${d})
-        break()
-      endif()
-    endforeach()
-  endif()
-
-  if(_CMAKE_OSX_SDKS_DIR)
-    # Select SDK for current OSX version accounting for the known
-    # specially named SDKs.
-    set(_CMAKE_OSX_SDKS_VER_SUFFIX_10.4 "u")
-    set(_CMAKE_OSX_SDKS_VER_SUFFIX_10.3 ".9")
-    if(CMAKE_OSX_DEPLOYMENT_TARGET)
-      set(_CMAKE_OSX_SDKS_VER ${CMAKE_OSX_DEPLOYMENT_TARGET}${_CMAKE_OSX_SDKS_VER_SUFFIX_${CMAKE_OSX_DEPLOYMENT_TARGET}})
-      set(_CMAKE_OSX_SYSROOT_CHECK "${_CMAKE_OSX_SDKS_DIR}/MacOSX${_CMAKE_OSX_SDKS_VER}.sdk")
-      if(IS_DIRECTORY "${_CMAKE_OSX_SYSROOT_CHECK}")
-        set(_CMAKE_OSX_SYSROOT_DEFAULT "${_CMAKE_OSX_SYSROOT_CHECK}")
-      else()
-        set(_CMAKE_OSX_SDKS_VER ${_CURRENT_OSX_VERSION}${_CMAKE_OSX_SDKS_VER_SUFFIX_${_CURRENT_OSX_VERSION}})
-        set(_CMAKE_OSX_SYSROOT_DEFAULT "${_CMAKE_OSX_SDKS_DIR}/MacOSX${_CMAKE_OSX_SDKS_VER}.sdk")
-        message(WARNING
-          "CMAKE_OSX_DEPLOYMENT_TARGET is '${CMAKE_OSX_DEPLOYMENT_TARGET}' "
-          "but the matching SDK does not exist at:\n \"${_CMAKE_OSX_SYSROOT_CHECK}\"\n"
-          "Instead using SDK:\n \"${_CMAKE_OSX_SYSROOT_DEFAULT}\"\n"
-          "matching the host OS X version."
-          )
-      endif()
-    else()
-      set(_CMAKE_OSX_SDKS_VER ${_CURRENT_OSX_VERSION}${_CMAKE_OSX_SDKS_VER_SUFFIX_${_CURRENT_OSX_VERSION}})
-      set(_CMAKE_OSX_SYSROOT_DEFAULT "${_CMAKE_OSX_SDKS_DIR}/MacOSX${_CMAKE_OSX_SDKS_VER}.sdk")
-    endif()
-  else()
-    # Assume developer files are in root (such as Xcode 4.5 command-line tools).
-    set(_CMAKE_OSX_SYSROOT_DEFAULT "")
-  endif()
-endif()
-
-# Set cache variable - end user may change this during ccmake or cmake-gui configure.
-# Choose the type based on the current value.
-set(_CMAKE_OSX_SYSROOT_TYPE STRING)
-foreach(v CMAKE_OSX_SYSROOT _CMAKE_OSX_SYSROOT_DEFAULT)
-  if("x${${v}}" MATCHES "/")
-    set(_CMAKE_OSX_SYSROOT_TYPE PATH)
-    break()
-  endif()
-endforeach()
-set(CMAKE_OSX_SYSROOT "${_CMAKE_OSX_SYSROOT_DEFAULT}" CACHE ${_CMAKE_OSX_SYSROOT_TYPE}
-  "The product will be built against the headers and libraries located inside the indicated SDK.")
-
-# Transform the cached value to something we can use.
-set(_CMAKE_OSX_SYSROOT_ORIG "${CMAKE_OSX_SYSROOT}")
-set(_CMAKE_OSX_SYSROOT_PATH "")
-if(CMAKE_OSX_SYSROOT)
-  if("x${CMAKE_OSX_SYSROOT}" MATCHES "/")
-    # This is a path to the SDK.  Make sure it exists.
-    if(NOT IS_DIRECTORY "${CMAKE_OSX_SYSROOT}")
-      message(WARNING "Ignoring CMAKE_OSX_SYSROOT value:\n ${CMAKE_OSX_SYSROOT}\n"
-        "because the directory does not exist.")
-      set(CMAKE_OSX_SYSROOT "")
-      set(_CMAKE_OSX_SYSROOT_ORIG "")
-    endif()
-    set(_CMAKE_OSX_SYSROOT_PATH "${CMAKE_OSX_SYSROOT}")
-  else()
-    # Transform the sdk name into a path.
-    execute_process(
-      COMMAND xcodebuild -sdk ${CMAKE_OSX_SYSROOT} -version Path
-      OUTPUT_VARIABLE _stdout
-      OUTPUT_STRIP_TRAILING_WHITESPACE
-      ERROR_VARIABLE _stderr
-      RESULT_VARIABLE _failed
-      )
-    if(NOT _failed AND IS_DIRECTORY "${_stdout}")
-      set(_CMAKE_OSX_SYSROOT_PATH "${_stdout}")
-      # For non-Xcode generators use the path.
-      if(NOT "${CMAKE_GENERATOR}" MATCHES "Xcode")
-        set(CMAKE_OSX_SYSROOT "${_CMAKE_OSX_SYSROOT_PATH}")
-      endif()
-    endif()
-  endif()
-endif()
-
 # Make sure the combination of SDK and Deployment Target are allowed
 if(CMAKE_OSX_DEPLOYMENT_TARGET)
   if("${_CMAKE_OSX_SYSROOT_PATH}" MATCHES "^.*/MacOSX([0-9]+\\.[0-9]+)[^/]*\\.sdk")