We usually build .tar.gz files for binary releases of Singular:
one with all the binary files, one with documentation and libraries.
To build the first one, follow the instructions in
ftp://www.mathematik.uni-kl.de/pub/Math ... src/README(in principle: ./configure && make install && make bindist).
The second can be downloaded as Singular-<version>-share.tar.gz.
As far as I know the rpm build process start from these 2 .tar.gz files.