Description of problem:
xulrunner-7.0-1.fc15.src.rpm build fails without
/usr/lib/pkgconfig/cairo-tee.pc; that was first available in
cairo-devel-1.10.2-2, but the xulrunner SRPM "Requires" is
only "cairo-devel >= 1.6.0".

Version-Release number of selected component (if applicable):
xulrunner-7.0-1.fc15.src.rpm

How reproducible:
100%

Steps to Reproduce:
On an F14 system (with cairo-devel-1.10.2-1, from F14 updates), try to
build F15 xulrunner-7.0:
1. rpm --install xulrunner-7.0-1.fc15.src.rpm
2. rpmbuild -bb SPECS/xulrunner.spec

Or, take it on faith that cairo-tee.pc is needed for the build, and inspect 
the following packages to see what provides it:

  $ rpmls cairo-devel-1.10.2-1.fc14.i686.rpm | grep cairo-tee.pc
  (nothing)
  $ rpmls cairo-devel-1.10.2-3.fc15.i686.rpm | grep cairo-tee.pc
  -rw-r--r--  /usr/lib/pkgconfig/cairo-tee.pc

And the changelog for cairo-devel-1.10.2-3.fc15.i686.rpm includes this:
 * Mon Jan 24 2011 Christopher Aillon <caillon> - 1.10.2-2
 - Enable tee support

Actual results:
From the rpmbuild:
checking for cairo-tee >= 1.10... Package cairo-tee was not found ...
configure: error: Library requirements (cairo-tee >= 1.10) not met; ...

Expected results:
Build proceeds.

Additional info:
  $ rpm -qRp xulrunner-7.0-1.fc15.src.rpm | grep cairo-devel
  cairo-devel >= 1.6.0

(So why am I building this under F14?  Well, GNOME 3/3.2 seems to be a
giant step backwards, so I'm still running F14, but with a good dose of
F15 and F16 packages.)