You can now define per-subproject values for all shared configuration options. As an example you might want to enable optimizations on only one subproject:
meson configure -Dnumbercruncher:optimization=3
Subproject specific values can be removed with -U
meson configure -Unumbercruncher:optimization
This is a major change in how options are handled, and the implementation will evolve over the next few releases of Meson. If this change causes an error in your builds, please report an issue on GitHub.
We have tried to keep backwards compatibility as much as possible, but this may lead to some build breakage.