Can't rebuild emacs RPM in F12

[Andrew Haley <aph redhat com>]

I have installed emacs-23.1-10.fc12.src.rpm

Then, when I run

 $ rpmbuild -ba emacs.spec

I get

...
+ /usr/bin/make bootstrap
(cd src;      /usr/bin/make  bootstrap-clean)
make[1]: Entering directory `/home/aph/rpmbuild/BUILD/emacs-23.1/src'
Makefile:103: *** commands commence before first target.  Stop.
make[1]: Leaving directory `/home/aph/rpmbuild/BUILD/emacs-23.1/src'

I can't understand this at all.  I tried it on two F12 installations.
Surely someone must have built emacs?

This is x86_64, BTW.

Andrew.