Pre-compute object file names before Xcode generation
Build object library targets in Xcode

Treat OBJECT libraries as STATIC libraries. The Xcode project file
format provides no way to avoid running the libtool so hide the
resulting .a away next to the object files as it should never be
referenced.  The object files will be left behind for reference by other
targets later.
Merge branch 'object-library' into xcode-object-library
Xcode: Honor $<TARGET_OBJECTS:...> source expressions

Add objects from object libraries referenced using this syntax to the
set of objects linked in a target.
Merge branch 'object-library' into xcode-object-library
Merge branch 'xcode-object-library' into object-library

* xcode-object-library:
  Xcode: Honor $<TARGET_OBJECTS:...> source expressions
  Build object library targets in Xcode
  Pre-compute object file names before Xcode generation
  Allow txt files as ExtraSources in object library targets
  Add a default source group for object files.
  Xcode: Re-factor some existing methods into "FromPath" variants
  Xcode: Re-factor code into GetObjectsNormalDirectory method
Merge branch 'ninja-object-library' into object-library

* ninja-object-library: (37 commits)
  Ninja: Honor $<TARGET_OBJECTS:...> source expressions
  Build object library targets in Ninja
  Pre-compute object file names before Ninja generation
  Simplify cmNinjaTargetGenerator using cmGeneratorTarget
  Ninja: Avoid using 'this' in member initializers
  Ninja: Fix for PDB files with spaces in the path.
  Ninja: Constify use of cmCustomCommand
  Ninja: add /DEF: flag to linker call
  Ninja: Add a cache option CMAKE_ENABLE_NINJA to enable the ninja generator.
  Ninja: Add friend struct so it can access the private ConvertToNinjaPath.
  Ninja: add .def file support
  Ninja: ensure the output dir exists at compile time
  Ninja: Remove an unnecessary variable
  Ninja: Use cmSystemTools::ExpandListArgument to split compile/link commands
  Ninja: Add a missed license header
  Ninja: CMake: Adapt Ninja generator for per-target include dirs
  Ninja: windows msvc: create for each target a .pdb file
  Ninja: Import library support for Windows
  Ninja: mark the Windows specific hacks with a comment only
  Ninja: disable unfinished Windows ninja support
  ...
Merge topic 'object-library' into next

93d5509 Merge branch 'ninja-object-library' into object-library
821037c Merge branch 'xcode-object-library' into object-library
eb24c99 Merge branch 'object-library' into xcode-object-library
63d1be8 Xcode: Honor $<TARGET_OBJECTS:...> source expressions
020ba38 Merge branch 'object-library' into xcode-object-library
e8ea615 Build object library targets in Xcode
8045e17 Pre-compute object file names before Xcode generation
247a132 Allow txt files as ExtraSources in object library targets
b063599 Add a default source group for object files.
be01f3b Xcode: Re-factor some existing methods into "FromPath" variants
2693dbe Merge branch 'object-library' into ninja-object-library
51997cb Ninja: Honor $<TARGET_OBJECTS:...> source expressions
23ec258 Merge branch 'object-library' into ninja-object-library
61124de Build object library targets in Ninja
f5b06cd Pre-compute object file names before Ninja generation
a2514f1 Simplify cmNinjaTargetGenerator using cmGeneratorTarget
...