Scope of changes
 There are two methods of building from source.  One is to independently install the source using rpm -i and then build from the already installed source using rpmbuild, the second is to use rpmbuild to install and build the source in a single step.  We want these changes to effect both methods of operation and therefore we must consider the behavior of both rpm -i and rpmbuild -b?|-t?|--rebuild|--recompile.
Currently, only rpm -i will accept any sort of remote URL, such as http://....  Additionally, rpm -i will not invoke a build process.  Only rpmbuild will actually invoke a build process.  And rpmbuild will only work on local files or already installed sources, it will never check for or use a remote URL.  I propose that we maintain this separation of operation.  This will limit all of the changes relating to downloading of source to rpm -i, and limit all changes relating to building of source to rpmbuild.