Add travis build configuration
Add travis build configuration

This travis configuration tests libvirt builds on 5 platforms that we don't
exercise in the CentOS CI system.

  - Ubuntu Trusty with GCC
  - Ubuntu Trusty with CLang
  - Ubuntu Precise with GCC
  - Ubuntu Precise with CLang
  - OS-X with CLang

NB, syntax-check fails on OS-X with errors like:

   /bin/sh: /usr/bin/grep: Argument list too long

Presumably their grep impl isn't as good as the GNU one, so this test
config skips syntax-check on OS-X for now.

Signed-off-by: Daniel P. Berrange <bb938cf255e055ff3507f2627d214e8e62118fcf@redhat.com>

nertpinx/libvirt,olafhering/libvirt,VenkatDatta/libvirt,fabianfreyer/libvirt,datto/libvirt,fabianfreyer/libvirt,fabianfreyer/libvirt,nertpinx/libvirt,datto/libvirt,andreabolognani/libvirt,libvirt/libvirt,crobinso/libvirt,andreabolognani/libvirt,andreabolognani/libvirt,jardasgit/libvirt,nertpinx/libvirt,libvirt/libvirt,eskultety/libvirt,zippy2/libvirt,VenkatDatta/libvirt,zippy2/libvirt,andreabolognani/libvirt,zippy2/libvirt,VenkatDatta/libvirt,jfehlig/libvirt,nertpinx/libvirt,olafhering/libvirt,datto/libvirt,jardasgit/libvirt,olafhering/libvirt,jardasgit/libvirt,eskultety/libvirt,jfehlig/libvirt,VenkatDatta/libvirt,libvirt/libvirt,nertpinx/libvirt,crobinso/libvirt,crobinso/libvirt,datto/libvirt,jfehlig/libvirt,fabianfreyer/libvirt,andreabolognani/libvirt,fabianfreyer/libvirt,jfehlig/libvirt,eskultety/libvirt,eskultety/libvirt,olafhering/libvirt,jardasgit/libvirt,datto/libvirt,libvirt/libvirt,zippy2/libvirt,crobinso/libvirt,jardasgit/libvirt,VenkatDatta/libvirt,eskultety/libvirt