m4: checking if ssh_get_server_publickey() exists.

This commit adds some checks inside libssh m4 checking to verify if
ssh_get_server_publickey is available. This new function scope replaces
the old ssh_get_publickey() from libssh 0.7.5 and below. Assuming that
some distros are not showing the right version of libssh. This is a
simple way to check which function is available.
Signed-off-by: NJulio Faracco <jcfaracco@gmail.com>
Reviewed-by: NAndrea Bolognani <abologna@redhat.com>

m4/virt-libssh.m4

@@ -23,6 +23,19 @@ AC_DEFUN([LIBVIRT_ARG_LIBSSH],[
 
 AC_DEFUN([LIBVIRT_CHECK_LIBSSH],[
   LIBVIRT_CHECK_PKG([LIBSSH], [libssh], [0.7])
+
+  if test "$with_libssh" = "yes" ; then
+    old_CFLAGS="$CFLAGS"
+    old_LIBS="$LIBS"
+    CFLAGS="$CFLAGS $LIBSSH_CFLAGS"
+    LIBS="$LIBS $LIBSSH_LIBS"
+    AC_CHECK_FUNC([ssh_get_server_publickey],
+      [],
+      [AC_DEFINE_UNQUOTED([ssh_get_server_publickey], [ssh_get_publickey],
+            [ssh_get_publickey is deprecated and replaced by ssh_get_server_publickey.])])
+    CFLAGS="$old_CFLAGS"
+    LIBS="$old_LIBS"
+  fi
 ])
 
 AC_DEFUN([LIBVIRT_RESULT_LIBSSH],[