[CheckStructHasMember] Add support for C++

If headers required to check if a struct has a member can be compiled
with C++ compiler only, the check will fail, because the C compiler
will fail.
As a consequence, the result variable is set to false, even if the
struct has that particular member.

The CHECK_C_STRUCT_HAS_MEMBER now accepts a new optional argument
LANGUAGE that allows one to explicitly set the compiler to use.
The new signature is therefore:

  CHECK_STRUCT_HAS_MEMBER (<struct> <member> <header> <variable>
                           [LANGUAGE <language>])
CMake Nightly Date Stamp
FindGTK: Specify languages used by tests

This will avoid checking for unneeded compilers, and should make tests
slightly faster.
Merge topic 'FindGTK2-targets' into next

0f2c22e FindGTK: Specify languages used by tests
FindGTK2: Avoid ctest truncation of output and make it verbose
Merge topic 'FindGTK2-targets' into next

b7c1516 FindGTK2: Avoid ctest truncation of output and make it verbose
CheckStructHasMember: Add unit tests
Merge topic 'CheckStructHasMember_CXX' into next

e66277d CheckStructHasMember: Add unit tests
945734e [CheckStructHasMember] Add support for C++
CheckStructHasMember: Add more unit tests
Merge topic 'deprecation-message' into CheckStructHasMember_CXX

Conflicts:
	Tests/RunCMake/CMakeLists.txt
Merge topic 'CheckStructHasMember_CXX' into next

b7f508f Merge topic 'deprecation-message' into CheckStructHasMember_CXX
e0f041f CheckStructHasMember: Add more unit tests
Xcode: Fix test architecture selection for Xcode >= 5

In Tests/Architecture and Tests/BuildDepends/Project we select a set of
OS X cpu architectures to use for the test.  Prior to Xcode 4 we always
used i386 and ppc.  Starting with Xcode 4, the tools do not support ppc
but do support x86_64, so we switch to that.  Fix the version check to
recognize Xcode >= 5 as at least Xcode 4 and use the new architectures.
Xcode: Teach Tests/BuildDepends to allow LINK_DEPENDS_NO_SHARED failure

Xcode 5.0 now relinks targets when their shared libraries dependencies
are modified, and there seems to be no way to stop it.  Report this as a
known limitation in the test output and do not fail.
Xcode: Drop XCODE_DEPEND_HELPER for Xcode >= 5

Xcode 5.0 now computes dependencies from files linked through
OTHER_LDFLAGS, so we no longer need the XCODE_DEPEND_HELPER hack to
re-link dependents when targets change.
Xcode: Fix OBJECT library support for Xcode 5 (#14254)

Xcode 2.1 through 4 supported $(CURRENT_ARCH) in a PBXFileReference
'path' value used in the "Link Binary with Libraries" build phase.
CMake uses this to reference object file locations on link lines to
bring in OBJECT library content.  However, Xcode 5 now evaluates the
$(CURRENT_ARCH) reference in this context as "undefined_arch" so the
wrong path is given to the linker.  There seems to be no alternative way
to produce an architecture-specific value in a PBXFileReference.

Fortunately Xcode 5 now also handles link dependencies for paths linked
through OTHER_LDFLAGS.  For Xcode >= 5, move the OBJECT library object
file references from the link build phase to OTHER_LDFLAGS.  We can
still show the object files in the source group listing in either case.
Merge topic 'xcode-5' into next

a3194ff Xcode: Fix OBJECT library support for Xcode 5 (#14254)
dff8d11 Xcode: Drop XCODE_DEPEND_HELPER for Xcode >= 5
1180322 Xcode: Teach Tests/BuildDepends to allow LINK_DEPENDS_NO_SHARED failure
765b46d Xcode: Fix test architecture selection for Xcode >= 5
c0133a5 CMake Nightly Date Stamp
export: Add policy CMP0024 to disallow include() of export files

Currently, export() is executed at configure-time.

One problem with this is that certain exported properties like
the link interface may not be complete at the point the export() is
encountered leading to an incorrect or incomplete exported
representation. Additionally, the generated IMPORTED_LOCATION
property may even be incorrect if commands following the export()
have an effect on it.

Another problem is that it requires the C++ implementation of cmake
to be capable of computing the exported information at configure time.
This is a limitation on the cleanup and maintenance of the code. At
some point in the future, this limitation will be dropped and more
implementation will be moved from cmTarget to cmGeneratorTarget.
Merge topic 'export-policy' into next

1ed1e78 export: Add policy CMP0024 to disallow include() of export files