We need to work on configure times, though. The largest gain (about 400% or so) can be had by generating configure from an old version of autoconf.
And a secondary rather large gain can be had by not having separate configure-scripts for each module, but instead generating a toplevel configure from the subconfigures or something.
And removing redundant and other rather unnessesary tests (I'm guilty here, I often add tests for each function even though the presence of one generally means that the others are available too, such as the {get,set,list,llist,lset,lget,fget,fset,flist}xattr methods I just added).
And also stopping the module configure scripts as soon as a required feature is found to be missing (as an example, in the GL module, when no GL library is found, stop looking for functions in the non existing library, and inversely, stop looking for more GL libraries once the first has been found)