[CMake] CMAKE_CXX_COMPILE_OBJECT for compiler with no -o support

[Trevor Kellaway]

Alex,

> Three ideas:
> - do as you suggest, use a wrapper
> - try whether you can get it working with something like 
> ${CMAKE_CURRENT_BINARY_DIR}/CMakeFiles/${_target}.dir
> - check the cmake source for "OBJECT" and if there is nothing 
> like "OBJECT_DIR write a patch and submit it 

>From looking at the source it turns out OBJECT_DIR has already been implemented! My proposal of OBJECT_DIR was just a suggestion, I didn't expect it to actually be there.

FYI, source file cmLocalGenerator.cxx function cmLocalGenerator::ExpandRuleVariable() has lots of useful (mostly undocumented) strings:

	ASSEMBLY_SOURCE
	FLAGS
	LANGUAGE_COMPILE_FLAGS
	LINK_FLAGS
	LINK_LIBRARIES
	OBJECT
	OBJECTS
	OBJECTS_QUOTED
	OBJECT_DIR
	PREPROCESSED_SOURCE
	SOURCE
	TARGET
	TARGET_BASE
	TARGET_IMPLIB
	TARGET_INSTALLNAME_DIR
	TARGET_PDB
	TARGET_QUOTED
	TARGET_SONAME
	TARGET_VERSION_MAJOR
	TARGET_VERSION_MINOR

Regards.