[webkit-dev] Features defines: Platform.h vs build system

[Balazs Kelemen]

     Hi all!

I think we lack a consistent way for setting up the set of feature 
defines. Some of them are handled via Platform.h and some of them via 
the build systems. Don't you think all should be handled the same way? 
This has came up in my mind in connection with the newly introduced 
CSS_FILTERS define. (https://bugs.webkit.org/show_bug.cgi?id=68652) The 
logic to set the define has only been added to the Mac build system 
because the feature is Mac-only currently. I don't think it is a good 
solution. As more platforms would use the feature they also need to add 
the logic to their build system that is somewhat more difficult than 
just adding one more ifdef branch to Platform.h. Note that it is not 
totally avoidable to have some overhead per platform because we need to 
handle the --css-filters build-webkit switch. However build-webkit 
already knows how to set up a -D flag on each platform so it's not a big 
deal.
I wonder about your opinion on this.

-kbalazs