[PATCH v5 0/4] Allow compiling dri2 without libdrm

[Pauli Nieminen]

These patches make it possible to use dri2 without libdrm. Dropping
libdrm support is done as optional compile time option to keep ABI/API
compability with older libdrm based drivers. 

In future libdrm could be dropped from xserver because libdrm should be
driver side implementation detail.

I rebased these patches to the latest xserver master. That includes
removal of malloc wrappers.