CentOS (RHEL) 5.4 kernel source
Say you want to build the source tree for a RHEL/CentOS 5.4 kernel (2.6.18-164.11.1.el5 in my case) and you are running a recent Debian or Fedora system. You might get patch failure errors.
… Just add this to fix it:
%define _default_patch_fuzz 2