[Libvir] PATCH: Remove use of PKG_CHECK_EXISTS

[Jim Meyering]

"Daniel P. Berrange" <berrange at redhat.com> wrote:
...
> Index: configure.in
> ===================================================================
> RCS file: /data/cvs/libvirt/configure.in,v
> retrieving revision 1.121
> diff -u -p -r1.121 configure.in
> --- configure.in	19 Jan 2008 18:36:01 -0000	1.121
> +++ configure.in	22 Jan 2008 17:21:27 -0000
...
> -if test "z$with_libxml" = "zno" ; then
> +if test "$with_libxml" = "no" ; then

It's good to leave some kind of prefix on tested values like that,
since the $with_libxml value is user-settable.
I.e., with your change, --with-libxml=-lt causes
a syntax error in the configure script:

    ./configure: line 27674: test: -z: integer expression expected

not that it matters much, because the very next thing
that happens is this:

    checking libxml2 -lt/bin/xml2-config >= 2.5.0 ... configure: error: \
      Could not find libxml2 anywhere (see config.log for details).

Otherwise (modulo long lines: max in the file is 260!), +1.
max in your patch is over 100.