gnucash stable: Add #ifdef __cplusplus extern "C" {} wrappers to .h files

[Christopher Lam]

Updated	 via  https://github.com/Gnucash/gnucash/commit/698cc230 (commit)
	from  https://github.com/Gnucash/gnucash/commit/ef094082 (commit)



commit 698cc23051e597f1f62d0b870edb30bf05d4d45c
Author: Christopher Lam <christopher.lck at gmail.com>
Date:   Mon Feb 5 21:22:07 2024 +0800

    Add #ifdef __cplusplus extern "C" {} wrappers to .h files



Summary of changes:
 libgnucash/engine/cap-gains.h | 8 ++++++++
 libgnucash/engine/gnc-lot-p.h | 8 ++++++++
 2 files changed, 16 insertions(+)