Actually the change is affecting only builds if
1.) Using cmake build
2.) on unix
To use it on
cygwin: one has to patch development/cygwin/lyxrc.dist.in
MacOSX: -//- development/MacOSX/lyxrc.dist.in
We need also a Windows-version
Also the compilation with automake lacks the handling of development/unix/lyxrc.dist.in