CPack: use IsOn instead of IsSet for boolean CPack options

The CPackComponent macros specifically set CPack options to FALSE
which CPack previously interpreted to mean "true".
Order cmGeneratorTargetsType elements deterministically.

Define a custom ordering functor to deterministically and strictly
order the cmTarget* key. Otherwise the order would be dependent on
runtime pointer values, which breaks assumptions of some generators.

The functor orders first by target name, and then by directory. Multiple
global targets may have the same name, such as edit_cache, but their
directory differentiates them.
Port some of the generator API to cmGeneratorTarget.

Just enough to reach the BuildMacContentDirectory method and the
NeedRelinkBeforeInstall methods.

In the future, those methods can be moved to cmGeneratorTarget.
FindSWIG: Mark SWIG_DIR & SWIG_VERSION as advanced (#13426)
FindSWIG: Search for swig.swg only on host (#13449)

Use NO_CMAKE_FIND_ROOT_PATH to ensure swig.swg can be found on the host
even when cross-compiling.
FindSWIG: Use CMAKE_CURRENT_LIST_DIR instead of CMAKE_ROOT (#13771)

This is a simpler way to reference the location of UseSWIG.cmake.
Eclipse: add -j only on UNIX hosts

The previous version added -jN to the make invokation if UNIX
was set, but this was true also when cross compiling.
What we are actually interested in is CMAKE_HOST_UNIX, i.e.
whether the build host is UNIX.
Or we should check more exactly what CMAKE_MAKE_PROGRAM is.

Alex
UseSWIG: Fix .i relative source file location (#13173,#13772,#14459)
Merge topic 'make-cpack-options-boolean'

5bc6444 CPack: use IsOn instead of IsSet for boolean CPack options
Merge topic 'use-generator-target'

c34968a Port some of the generator API to cmGeneratorTarget.
abb13ea Order cmGeneratorTargetsType elements deterministically.
Merge topic 'FindSWIG-fix13426'

6620dc7 FindSWIG: Mark SWIG_DIR & SWIG_VERSION as advanced (#13426)
Merge topic 'FindSWIG-fix13449'

19b7a54 FindSWIG: Search for swig.swg only on host (#13449)
Merge topic 'FindSWIG-fix13771'

8c127c9 FindSWIG: Use CMAKE_CURRENT_LIST_DIR instead of CMAKE_ROOT (#13771)
Merge topic 'UseSWIG-fix13772'

276e373 UseSWIG: Fix .i relative source file location (#13173,#13772,#14459)
Merge topic 'EclipseParallelMakeOnlyOnUnixHosts'

83751af Eclipse: add -j only on UNIX hosts
Help: Document $ENV{VAR} syntax in cmake-language.7 manual
Merge topic 'doc-cmake-language-env-vars'

45a03aa Help: Document $ENV{VAR} syntax in cmake-language.7 manual
Help: Organize and revise the cmake-generators.7 manual

Move "extra" generators to their own section instead of duplicating them
for each corresponding main generator.  Divide the list of main
generators into command-line and IDE sections and sort the names within
each section.  Document the environment from which each kind of
generator may be used.

Add a section to each "extra" generator documenting which main
generators may be used with it.
Merge topic 'doc-generators-cleanup'

beec9db Help: Organize and revise the cmake-generators.7 manual