Porting from macro_log_feature without a package to FeatureSummary?

[Stephen Kelly]

Hi,

The current feature_summary seems to require a package. Things like this 
work:

find_package(Foo)
set_package_properties(Foo ...)

But in solid we have:

find_program(BISON_EXECUTABLE bison) # ### Not find_package
macro_log_feature(bison ...)


Two ways out are:

* Add an equivalent feature to cmake
* Add a FindBison.cmake and find the package.



Regardless of whether cmake is modified to make this easier, I think we 
should have a FindBison anyway.

What do you think?

Steve.