configure: Introduce libiscsi in build system

The minimal required version is 1.18.0 because the synchrounous function
needed were introduced here.

Signed-off-by: Clementine Hayat <clem@lse.epita.fr>

configure.ac

@@ -251,6 +251,7 @@ LIBVIRT_ARG_FUSE
 LIBVIRT_ARG_GLUSTER
 LIBVIRT_ARG_HAL
 LIBVIRT_ARG_JANSSON
+LIBVIRT_ARG_LIBISCSI
 LIBVIRT_ARG_LIBPCAP
 LIBVIRT_ARG_LIBSSH
 LIBVIRT_ARG_LIBXML
@@ -292,6 +293,7 @@ LIBVIRT_CHECK_GLUSTER
 LIBVIRT_CHECK_GNUTLS
 LIBVIRT_CHECK_HAL
 LIBVIRT_CHECK_JANSSON
+LIBVIRT_CHECK_LIBISCSI
 LIBVIRT_CHECK_LIBNL
 LIBVIRT_CHECK_LIBPARTED
 LIBVIRT_CHECK_LIBPCAP
@@ -973,6 +975,7 @@ LIBVIRT_RESULT_GLUSTER
 LIBVIRT_RESULT_GNUTLS
 LIBVIRT_RESULT_HAL
 LIBVIRT_RESULT_JANSSON
+LIBVIRT_RESULT_LIBISCSI
 LIBVIRT_RESULT_LIBNL
 LIBVIRT_RESULT_LIBPCAP
 LIBVIRT_RESULT_LIBSSH

m4/virt-libiscsi.m4

@@ -0,0 +1,30 @@
+dnl Libiscsi library
+dnl
+dnl Copyright (C) 2018 Clementine Hayat.
+dnl
+dnl This library is free software; you can redistribute it and/or
+dnl modify it under the terms of the GNU Lesser General Public
+dnl License as published by the Free Software Foundation; either
+dnl version 2.1 of the License, or (at your option) any later version.
+dnl
+dnl This library is distributed in the hope that it will be useful,
+dnl but WITHOUT ANY WARRANTY; without even the implied warranty of
+dnl MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+dnl Lesser General Public License for more details.
+dnl
+dnl You should have received a copy of the GNU Lesser General Public
+dnl License along with this library.  If not, see
+dnl <http://www.gnu.org/licenses/>.
+dnl
+
+AC_DEFUN([LIBVIRT_ARG_LIBISCSI],[
+  LIBVIRT_ARG_WITH_FEATURE([LIBISCSI], [libiscsi], [check], [1.18.0])
+])
+
+AC_DEFUN([LIBVIRT_CHECK_LIBISCSI],[
+  LIBVIRT_CHECK_PKG([LIBISCSI], [libiscsi], [1.18.0])
+])
+
+AC_DEFUN([LIBVIRT_RESULT_LIBISCSI],[
+  LIBVIRT_RESULT_LIB(LIBISCSI)
+])