gnucash maint: Bomb out immediately if or aren't set

[John Ralls]

Updated	 via  https://github.com/Gnucash/gnucash/commit/76a4389a (commit)
	from  https://github.com/Gnucash/gnucash/commit/4aefc55a (commit)



commit 76a4389a9212d33e626b9441d5c57f490f6737d0
Author: John Ralls <jralls at ceridwen.us>
Date:   Thu Mar 25 13:53:14 2021 -0700

    Bomb out immediately if  or  aren't set
    
    Instead of spewing dozens of errors about file(TO_CMAKE_PATH) needing 3 parameters.



Summary of changes:
 common/cmake_modules/GncAddSchemeTargets.cmake | 3 +++
 1 file changed, 3 insertions(+)