please add support for displaying things like '#ifdef'

[chinyu0704]

hi,

I believe there are a bunch of people who work with large source code project like linux kernel. Nomally in a kernel source file , there are lots of "#ifdef CONFG_XXX " or "#else" macros inside which scope funciton has completely diffrent implementation. Thus everytime I have to jump to the specific function definition and press "[#" to see if I'm under some "#ifdef"; if the macro condition isn't right, I have to jump to another difinition.
So if taglist can support displaying those conditioning macros, that would be great!

thanks.