virhostcpu: Fix build with clang and newest kernel headers
virhostcpu: Fix build with clang and newest kernel headers

The most recent environment e.g. present in our Fedora Rawhide builds
fail to build the tree with clang with the following error:

../src/util/virhostcpu.c:1291:25: error: field 'header' with variable sized type 'struct kvm_msrs' not at the end of a struct or class is a GNU extension [-Werror,-Wgnu-variable-sized-type-not-at-end]
        struct kvm_msrs header;
                        ^

The problem seems to be that clang doesn't like the new way the
'entries' field in struct kvm_msrs is declared.

To work around the issue we can simply allocate the variable dynamically
and use the 'entries' member as it was intended to to access the
members.

Signed-off-by: Peter Krempa <2cf5c04c61aa466e4a47bfedc747d17279c72ffc@redhat.com>
Reviewed-by: Jiri Denemark <62bdf77dc47919a4d59a91822129d14633cfca81@redhat.com>

jfehlig/libvirt,jfehlig/libvirt,jfehlig/libvirt,zippy2/libvirt,jfehlig/libvirt,libvirt/libvirt,zippy2/libvirt,zippy2/libvirt,libvirt/libvirt,zippy2/libvirt,olafhering/libvirt,olafhering/libvirt,libvirt/libvirt,libvirt/libvirt,olafhering/libvirt,olafhering/libvirt