VS: Move VS-only API out of cmGlobalGenerator

Move the IsDependedOn method to cmGlobalVisualStudio7Generator
since that is the only caller.
VS: Fix subproject .sln dependencies on custom targets

Each project listed in a .sln must be marked (or not) as part of the
"default build" for each configuration.  For targets created by the
add_custom_target() command we add them to the default build if they
are not excluded in some way or if another target depends on them.
In the top-level .sln, a custom target is excluded if it is not
created with the ALL option to add_custom_target.  In subdirectory
.sln files, a target may also be excluded if it is not within the
directory and is brought into the solution only due to a dependency
from another target in the solution.

Fix the "IsPartOfDefaultBuild" and "IsDependedOn" methods to check
every target to be included in the .sln for a dependency on the
custom target.  Otherwise transitive dependencies through targets
not in the current subdirectory will not be considered.

Extend the SubProject test with a custom target to cover this case.

Reported-by: William Deurwaarder <William.Deurwaarder@tomtom.com>
Reported-by: Dirk Steenpass <dirk.steenpass@gmail.com>
cmake: Fix read-after-free while checking command-line arguments

Since commit v2.8.12~300^2~1 (CLI: Suppress the unused warning if the
key value pair is cached, 2013-05-16), cmake::SetCacheArgs saves a
cachedValue pointer and may cause the memory to be freed (by setting the
cache entry) before reading it again.  Fix this by saving the old value
in a separate string.
Merge topic 'fix-read-after-free' into next

23ffb72a cmake: Fix read-after-free while checking command-line arguments
Merge topic 'vs-subdir-sln-depends' into next

790e1677 VS: Fix subproject .sln dependencies on custom targets
5fba44cf VS: Move VS-only API out of cmGlobalGenerator