Mine

darkapostrophe@Liberty:~/downloads/iwlwifi-1.1.20$ make
Checking kernel compatibility in:
        /lib/modules/2.6.22-2-amd64/source
 * Kernel requires compatibility version:
   - Uses preferred_rate_control feature
Building compatibility version in 'compatible/' directory:
Copying compatible/ from origin/...done
 + Applying: patches/10-preferred_rate_control.patch
        diff -urp origin/iwl3945-base.c new/iwl3945-base.c
make -C /lib/modules/2.6.22-2-amd64/source O=/lib/modules/2.6.22-2-amd64/build M=/home/darkapostrophe/downloads/iwlwifi-1.1.20/compatible/ EXTRA_CFLAGS="-DCONFIG_IWLWIFI_DEBUG=y -DCONFIG_IWLWIFI_SPECTRUM_MEASUREMENT=y -DCONFIG_IWLWIFI_HT=y -DCONFIG_IWLWIFI_HT_AGG=y -DCONFIG_IWLWIFI_SENSITIVITY=y -DCONFIG_IWLWIFI_QOS=y" modules
make[1]: Entering directory `/usr/src/linux-source-2.6.22'
  CC [M]  /home/darkapostrophe/downloads/iwlwifi-1.1.20/compatible/iwl3945-base.o
/home/darkapostrophe/downloads/iwlwifi-1.1.20/compatible/iwl3945-base.c: In function ‘iwl_pci_probe’:
/home/darkapostrophe/downloads/iwlwifi-1.1.20/compatible/iwl3945-base.c:8336: error: ‘struct ieee80211_hw’ has no member named ‘preferred_rate_control’
make[3]: *** [/home/darkapostrophe/downloads/iwlwifi-1.1.20/compatible/iwl3945-base.o] Error 1
make[2]: *** [_module_/home/darkapostrophe/downloads/iwlwifi-1.1.20/compatible] Error 2
make[1]: *** [modules] Error 2
make[1]: Leaving directory `/usr/src/linux-source-2.6.22'
make: *** [modules] Error 2