Jan Danielsson wrote:
> And nowadays, we have build systems which patch the configure script
> (on top of them being automatically generated?) to make programs build
> properly.

I think that's pretty rare, and unnecessary for a well done configure
script.  The whole purpose of the configure script is to interrogate the
system (and user) to discover what feature set to build and where required
inputs are to be found.  A pkgsrc maintainer "should" need only set
configure's inputs, not hack the script itself.  

But, as you yourself found, autoconf is a subspecialty all its own, and
not everyone gets it right.  When they don't, the maintainer resorts to,
um, unorthodox methods.  

--jkl