We failed to include the pciaccess header flags in our build. Even if the
server was to include those flags for us, it would leave us broken for the
tools-only case, and it's easier to just put the flags everywhere so we avoid
future copy'n'paste mistakes.
Detect whether the target X server uses libpciaccess, using it in the driver
compilation as necessary. This change means that utilities that used to use
libpciaccess will not do so unless the driver itself uses libpciaccess. Yes,
that could be fixed, but it doesn't seem that important.
This patch does not include any code changes necessary to actually have the
driver build against an X server using libpciaccess.
xf86Modes.h file signals the availability of the new modes API in the
server; use that instead of counting on X server version numbers.
Also, finish eliminating use of local copies of those header files.