This LFS script allows to extract supported PCI IDs from X.org drivers, by dlopen()ing them http://wiki.linuxfromscratch.org/livecd/browser/trunk/packages/xorg-udev-rules/extract_pci_ids.c

For the record, the Makefile uses a weird trick to export Xorg symbols /o\

nm -D /usr/bin/Xorg | egrep ' (B|D) ' | cut -d ' ' -f 3 | grep -v __