I was able to get this to "build" locally, but received this error on FreeBSD. I was not able to get it to build outside of my machine, as it appears there is some other new dependency that is required to build that I am not figuring out, but I have it installed on my box.

gmake[3]: Entering directory `/usr/home/jgh/workspace/ports/devel/libvirt/work/libvirt-1.1.1/src'
  CC       libvirt_util_la-viralloc.lo
  CC       libvirt_util_la-virarch.lo
  CC       libvirt_util_la-viratomic.lo
  CC       libvirt_util_la-viraudit.lo
  CC       libvirt_util_la-virauth.lo
  CC       libvirt_util_la-virauthconfig.lo
  CC       libvirt_util_la-virbitmap.lo
  CC       libvirt_util_la-virbuffer.lo
  CC       libvirt_util_la-vircgroup.lo
util/vircgroup.c: In function 'virCgroupAvailable':
util/vircgroup.c:75: error: storage size of 'entry' isn't known
util/vircgroup.c:85: warning: implicit declaration of function 'getmntent_r'
util/vircgroup.c:85: warning: nested extern declaration of 'getmntent_r' [-Wnested-externs]
util/vircgroup.c:85: warning: comparison between pointer and integer
util/vircgroup.c:75: warning: unused variable 'entry' [-Wunused-variable]
gmake[3]: *** [libvirt_util_la-vircgroup.lo] Error 1
gmake[3]: Leaving directory `/usr/home/jgh/workspace/ports/devel/libvirt/work/libvirt-1.1.1/src'
gmake[2]: *** [all] Error 2
gmake[2]: Leaving directory `/usr/home/jgh/workspace/ports/devel/libvirt/work/libvirt-1.1.1/src'
gmake[1]: *** [all-recursive] Error 1
gmake[1]: Leaving directory `/usr/home/jgh/workspace/ports/devel/libvirt/work/libvirt-1.1.1'
gmake: *** [all] Error 2