maint: detect clang 2.9
maint: detect clang 2.9

In Fedora 15, with clang 2.8, 'scan-build env' shows:
CCC_ANALYZER_ANALYSIS=-analyzer-check-objc-mem -analyzer-check-security-syntactic -analyzer-check-dead-stores -analyzer-check-objc-unused-ivars -analyzer-check-objc-methodsigs

But in rawhide, with clang 2.9, the same variable is set but
empty, implying the default set of analysis.  We still want
sa_assert defined in that case, to stop clang from hitting
false positives.

* configure.ac (STATIC_ANALYSIS): Detect clang even when the set
of analyses is the default.

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