BUG: Fix issue #3648 - make sure CMake reruns if a Bundle application's directory is removed or if it's Info.plist file disappears since those elements are put in place at CMake configure time.

A Mac OS X Framework should provide a Resources/Info.plist file
containing meta-data about the framework.  This change generates a
default Info.plist for frameworks and provides an interface for users to
customize it.

This change cleans up the implementation of cmXCodeObject to avoid
un-escaping and re-escaping string values.  There is no need to store
the string in escaped form.  It can be escaped once when it is printed
out to the generated project file.

The recent fix to avoid including flags in dependency inferral also
dropped them from chaining of dependencies through targets.  This fix
restores chaining of flags through known dependency lists while still
leaving them out of inferred dependency lists.

This change introduces a new algorithm for link line construction.  The
order it computes always begins with the exact link line specified by
the user.  Dependencies of items specified by the user are tracked, and
those that are not already satisified by the line are appended to it at
the end with minimal repeats.  This restores the behavior of CMake 2.4
and below while still fixing some of its bugs.  See issue #7546.

In cmComputeLinkDepends link items that look like flags (starting in
'-') should not be included in dependency inferral.  They are not
libraries and therefore have no dependencies.  They should just be
passed through to the final link line unchanged.  See issue #7546.

In cmComputeLinkDepends we should treat an empty configuration name as
equivalent to no specific configuration at all.

This introduces the unset() command to make it easy to unset CMake
variables, environment variables, and CMake cache variables.  Previously
it was not even possible to unset ENV or CACHE variables (as in
completely remove them).  Changes based on patch from Philip Lowman.
See issue #7507.

ENH: Add the RECURSE_SYMLINKS_OFF flag to the FILE GLOB_RECURSE command. Exposes the recently added kwsys capability that prevents recursing through symlinks to CMake scripts.

Some native build tools, particularly those for cross compiling, may
have a limit on the length of the full path to an object file name that
is lower than the platform otherwise supports.  This change allows the
limit to be set by the project toolchain file through the variable
CMAKE_OBJECT_PATH_MAX.

ENH: Add RecurseThroughSymlinks data member to kwsys::Glob. Allows recursive globs to skip symlinks when necessary. Default to true for backwards compatible behavior. Used from the ctest coverage handler to avoid recursing through the '/Applications' directory on the Mac looking for *.da files... Should fix the hangs reported recently by Mac CMake dashboard submitters.

It is useful to be able to test if a target has been created.  Often
targets are created only inside conditions.  Rather than storing the
result of the condition manually for testing by other parts of the
project, it is much easier for the other parts to just test for the
target's existence.  This will also be useful when find-modules start
reporting results with IMPORTED targets and projects want to test if a
certain target is available.

According to "man select" on Linux it is possible that select() lies
about data being ready on a pipe in some subtle cases.  We deal with
this by switching to non-blocking i/o and checking for EAGAIN.  See
issue #7180.

BUG: fix for 6794 support for LTCG WholeProgramOptimization, which is not available in VS 8 and newer.