build: fix autogen rule for VPATH build
build: fix autogen rule for VPATH build

* cfg.mk (gnulib_srcdir): Override maint.mk default.
(_update_required): Run in correct directory.

zhlcindy/libvirt-1.1.4-maintain,amery/libvirt-vserver,cbosdo/libvirt,eskultety/libvirt,jeckersb/libvirt,cbosdo/libvirt,emaste/libvirt,zhlcindy/libvirt-1.1.4-maintain,fabianfreyer/libvirt,usc-isi/libvirt,novel/fbsd-libvirt,shugaoye/libvirt,emaste/libvirt,nertpinx/libvirt,danwent/libvirt-ovs,bjzhang/libvirt,rmarwaha/libvirt1,wiedi/libvirt,amery/libvirt-vserver,usc-isi/libvirt,VenkatDatta/libvirt,crobinso/libvirt,olafhering/libvirt,dumbbell/libvirt,rmarwaha/libvirt,taget/libvirt,jeckersb/libvirt,iam-TJ/libvirt,rlaager/libvirt,dumbbell/libvirt,trainstack/libvirt,siboulet/libvirt-openvz,dumbbell/libvirt,dumbbell/libvirt,leilihh/libvirt,shugaoye/libvirt,andreabolognani/libvirt,rmarwaha/libvirt1,VenkatDatta/libvirt,taget/libvirt,VenkatDatta/libvirt,foomango/libvirt,fabianfreyer/libvirt,novel/fbsd-libvirt,emaste/libvirt,kantai/libvirt-vfork,shugaoye/libvirt,amery/libvirt-vserver,novel/fbsd-libvirt,bjzhang/libvirt,datto/libvirt,kantai/libvirt-vfork,wiedi/libvirt,libvirt/libvirt,jeckersb/libvirt,cbosdo/libvirt,nertpinx/libvirt,iam-TJ/libvirt,olafhering/libvirt,rlaager/libvirt,rbu/libvirt,usc-isi/libvirt,iam-TJ/libvirt,agx/libvirt,jardasgit/libvirt,andreabolognani/libvirt,libvirt/libvirt,warewolf/libvirt,iam-TJ/libvirt,rbu/libvirt,rmarwaha/libvirt,novel/fbsd-libvirt,agx/libvirt,nertpinx/libvirt,jfehlig/libvirt,eskultety/libvirt,rmarwaha/libvirt,libvirt/libvirt,datto/libvirt,agx/libvirt,zippy2/libvirt,zippy2/libvirt,amery/libvirt-vserver,jardasgit/libvirt,kantai/libvirt-vfork,soulxu/libvirt-xuhj,VenkatDatta/libvirt,novel/fbsd-libvirt,novel/fbsd-libvirt,eskultety/libvirt,wiedi/libvirt,trainstack/libvirt,wiedi/libvirt,rbu/libvirt,elmarco/libvirt,zippy2/libvirt,elmarco/libvirt,wiedi/libvirt,taget/libvirt,leilihh/libvirt,sshah-solarflare/Libvirt-PCI-passthrough-,siboulet/libvirt-openvz,eskultety/libvirt,warewolf/libvirt,rmarwaha/libvirt,agx/libvirt,trainstack/libvirt,datto/libvirt,amery/libvirt-vserver,soulxu/libvirt-xuhj,danwent/libvirt-ovs,bjzhang/libvirt,rmarwaha/libvirt1,warewolf/libvirt,jfehlig/libvirt,shugaoye/libvirt,crobinso/libvirt,warewolf/libvirt,foomango/libvirt,iam-TJ/libvirt,rlaager/libvirt,iam-TJ/libvirt,sshah-solarflare/Libvirt-PCI-passthrough-,bjzhang/libvirt,jfehlig/libvirt,andreabolognani/libvirt,iam-TJ/libvirt,sshah-solarflare/Libvirt-PCI-passthrough-,jardasgit/libvirt,zippy2/libvirt,sshah-solarflare/Libvirt-PCI-passthrough-,trainstack/libvirt,shugaoye/libvirt,fabianfreyer/libvirt,jeckersb/libvirt,dumbbell/libvirt,elmarco/libvirt,wiedi/libvirt,taget/libvirt,siboulet/libvirt-openvz,olafhering/libvirt,crobinso/libvirt,kantai/libvirt-vfork,warewolf/libvirt,siboulet/libvirt-openvz,rlaager/libvirt,rbu/libvirt,novel/fbsd-libvirt,usc-isi/libvirt,zhlcindy/libvirt-1.1.4-maintain,elmarco/libvirt,trainstack/libvirt,danwent/libvirt-ovs,jeckersb/libvirt,danwent/libvirt-ovs,foomango/libvirt,leilihh/libvirt,agx/libvirt,rmarwaha/libvirt,fabianfreyer/libvirt,leilihh/libvirt,nertpinx/libvirt,rmarwaha/libvirt,jeckersb/libvirt,emaste/libvirt,jardasgit/libvirt,leilihh/libvirt,andreabolognani/libvirt,rlaager/libvirt,olafhering/libvirt,nertpinx/libvirt,usc-isi/libvirt,warewolf/libvirt,trainstack/libvirt,siboulet/libvirt-openvz,trainstack/libvirt,andreabolognani/libvirt,rmarwaha/libvirt1,libvirt/libvirt,jardasgit/libvirt,datto/libvirt,fabianfreyer/libvirt,soulxu/libvirt-xuhj,eskultety/libvirt,emaste/libvirt,crobinso/libvirt,wiedi/libvirt,jfehlig/libvirt,danwent/libvirt-ovs,soulxu/libvirt-xuhj,emaste/libvirt,sshah-solarflare/Libvirt-PCI-passthrough-,dumbbell/libvirt,novel/fbsd-libvirt,foomango/libvirt,cbosdo/libvirt,VenkatDatta/libvirt,leilihh/libvirt,warewolf/libvirt,zhlcindy/libvirt-1.1.4-maintain,rbu/libvirt,taget/libvirt,soulxu/libvirt-xuhj,rmarwaha/libvirt1,elmarco/libvirt,emaste/libvirt,jeckersb/libvirt,kantai/libvirt-vfork,rmarwaha/libvirt1,zhlcindy/libvirt-1.1.4-maintain,datto/libvirt,novel/fbsd-libvirt,bjzhang/libvirt,cbosdo/libvirt,foomango/libvirt