Introduce target property <LANG>_VISIBILITY_PRESET

This is initialized by CMAKE_<LANG>_VISIBILITY_PRESET. The target
property is used as the operand to the -fvisibility= compile option
with GNU compilers and clang.
Add a COMPILE_OPTION for a VISIBILITY_INLINES_HIDDEN target property.

This corresponds to the g++ and clang++
option -fvisibility-inlines-hidden on linux. On Windows with MinGW,
this corresponds to -fno-keep-inline-dllexport. That option is
not supported by clang currently.
Introduce add_compile_options command.

This command is similar to add_definitions, in that it affects
the compile options of all targets which follow it. The implementation
is similar to the implementation of the include_directories command,
in that it is based on populating a COMPILE_OPTIONS directory property
and using that to initialize the same property on targets.

Unlike the include_directories command however, the add_compile_options
command does not affect previously defined targets. That is, in
the following code, foo will not be compiled with -Wall, but bar
will be:

 add_library(foo ...)
 add_compile_options(-Wall)
 add_library(bar ...)
Remove unused cmAddDefinitionsCommand::ParseDefinition method.
Add some spaces to the INCLUDE_DIRECTORIES documentation.
CLI: Suppress the unused warning if the key value pair is cached.

It is common to specify a CMAKE_TOOLCHAIN_FILE and get a warning
for using it despite it not being used.

The WarnUnusedCliUnused test relies on the warning being emitted
each time cmake is run on an existing build. That behavior is changed
by this patch to warn only on the first invokation of CMake, and not
on subsequent invokations (because the variable is in the cache with
the same value). For that test, a clean target is added which clears
the cache and cause the warning to be emitted each time.

As the Ninja generator does not support the feature needed to test
this, it is not tested with that generator.
Docs: Clarify CMAKE_PARENT_LIST_FILE (#14194)

Fix the wording of the documentation for CMAKE_PARENT_LIST_FILE to
clarify that it only applies to the include stack in the current
directory.  Specify exactly what commands can include files instead of
saying "somehow invoke".
KWSys 2013-06-03 (d79a792e)

Extract upstream KWSys using the following shell commands.

$ git archive --prefix=upstream-kwsys/ d79a792e | tar x
$ git shortlog --no-merges --abbrev=8 --format='%h %s' dccf7725..d79a792e
Brad King (1):
      d79a792e SystemTools: Fix CollapseFullPath to not erase root component

Change-Id: I25c6600a621a960738b5afc0ba73f63df0693303
Merge branch 'upstream-kwsys' into update-kwsys
get_filename_component: Test ABSOLUTE of .. after root component

Teach the RunCMake.get_filename_component test to verify that ".." does
not remove the root filename component.
Xcode: Fix framework search paths in STATIC library targets (#14191)

In commit 2bc22bda (Xcode: Add frameworks search paths from link
dependeny closure, 2012-12-07) we made framework search paths from the
link closure conditional on target type, skipping it on STATIC and
OBJECT library targets that do not actually link.  However, the
framework search paths also influence the compile lines (-F options) so
we need them for all target types.  The Makefile generator already does
this, as did the Xcode generator prior to the above-mentioned commit.
Genex: Fix the HEAD target used for evaluated expressions

If the expression $<TARGET_PROPERTY:prop> appears in the content
of a target property, the target that prop is read from is
the 'head target' of the expression. In contexts such as evaluating
the content of a target property during generation, such
as INCLUDE_DIRECTORIES, the 'head target' is the one on which the
initial request was made.

If evaluating a generator expression which is not a target property
content, the target must be explicitly specified. Such contexts
include add_custom_command and file(GENERATE). The content might
then look like

 $<TARGET_PROPERTY:tgt,prop>

However, as there is no HeadTarget set, any generator expressions
evaluated as part of reading prop from tgt which do not specify
the tgt directly report an error.

Modify the logic of the TARGET_PROPERTY generator expression so
that in such contexts, the 'head target' is set to the appropriate
target which was first encountered.
Merge topic 'VISIBILITY_PRESET-property'

cd1fa53 Add a COMPILE_OPTION for a VISIBILITY_INLINES_HIDDEN target property.
0e9f4bc Introduce target property <LANG>_VISIBILITY_PRESET
Merge topic 'add_compile_options-command'

a984f32 Introduce add_compile_options command.
Merge topic 'cleanups'

9efe359 Add some spaces to the INCLUDE_DIRECTORIES documentation.
db15713 Remove unused cmAddDefinitionsCommand::ParseDefinition method.
Merge topic 'suppress-unused-cli-with-value-in-cache'

273ecab CLI: Suppress the unused warning if the key value pair is cached.
Merge topic 'doc-CMAKE_PARENT_LIST_FILE'

b62d440 Docs: Clarify CMAKE_PARENT_LIST_FILE (#14194)
Merge topic 'update-kwsys'

c91e88d Merge branch 'upstream-kwsys' into update-kwsys
6dc3dd9 KWSys 2013-06-03 (d79a792e)
Merge topic 'fix-path-root-dot-dot'

d26800b get_filename_component: Test ABSOLUTE of .. after root component
Merge topic 'xcode-framework-paths'

21a0bea Xcode: Fix framework search paths in STATIC library targets (#14191)