gnucash-docs maint: Multiple changes pushed

[John Ralls]

Updated	 via  https://github.com/Gnucash/gnucash-docs/commit/afef9670 (commit)
	 via  https://github.com/Gnucash/gnucash-docs/commit/59013c31 (commit)
	 via  https://github.com/Gnucash/gnucash-docs/commit/2422e674 (commit)
	from  https://github.com/Gnucash/gnucash-docs/commit/bdd42fe5 (commit)



commit afef9670092daeed882b7cc6d556342ab5dedf04
Author: John Ralls <jralls at ceridwen.us>
Date:   Fri Jul 8 16:42:32 2022 -0700

    Only build GHelp files by default on Unix-not-Apple
    
    Windows and macOS don't have Yelp so it's not useful.

commit 59013c31d26c15ff56b0ee7afff49a57bb0d2bba
Author: John Ralls <jralls at ceridwen.us>
Date:   Fri Jul 8 16:24:24 2022 -0700

    Create ${DATADIR_BUILD}/gnome only when making the GHelp target.

commit 2422e674ade7ce3a38aa4af1fd3711bb59ab19b9
Author: John Ralls <jralls at ceridwen.us>
Date:   Fri Jul 8 16:09:08 2022 -0700

    Create ${DOCDIR_BUILD} only if one of the targets that needs it is built.



Summary of changes:
 CMakeLists.txt             |  4 ++++
 cmake/AddEpubTarget.cmake  |  2 +-
 cmake/AddGHelpTarget.cmake | 12 ++++++++----
 cmake/AddHtmlTarget.cmake  | 14 ++++++--------
 cmake/AddPdfTarget.cmake   |  2 +-
 5 files changed, 20 insertions(+), 14 deletions(-)