gnucash stable: Doxygen: Set header version to VCS version if building from VCS

[John Ralls]

Updated	 via  https://github.com/Gnucash/gnucash/commit/828a80d0 (commit)
	from  https://github.com/Gnucash/gnucash/commit/0fe7389e (commit)



commit 828a80d0bc48a4b46ba6f1e3743e2a1f898a4c01
Author: John Ralls <jralls at ceridwen.us>
Date:   Thu Jul 16 13:46:34 2026 -0700

    Doxygen: Set header version to VCS version if building from VCS



Summary of changes:
 CMakeLists.txt | 9 +++++++++
 doxygen.cfg.in | 2 +-
 2 files changed, 10 insertions(+), 1 deletion(-)