block/iscsi: Fix compilation for libiscsi 1.4.0 (API change)

Function iscsi_read10_task got additional parameters starting with version
libiscsi 1.5.0.

libiscsi 1.4.0 is still widely used (Debian wheezy, jessie and other Linux
distributions currently provide packages for QEMU which use it), so we
still need support for this older API.
Reviewed-by: NPeter Lieven <pl@kamp.de>
Signed-off-by: NStefan Weil <sw@weilnetz.de>
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>

block/iscsi.c

@@ -359,7 +359,10 @@ retry:
     default:
         iTask.task = iscsi_read10_task(iscsilun->iscsi, iscsilun->lun, lba,
                                        num_sectors * iscsilun->block_size,
-                                       iscsilun->block_size, 0, 0, 0, 0, 0,
+                                       iscsilun->block_size,
+#if !defined(CONFIG_LIBISCSI_1_4) /* API change from 1.4.0 to 1.5.0 */
+                                       0, 0, 0, 0, 0,
+#endif
                                        iscsi_co_generic_cb, &iTask);
         break;
     }

configure

@@ -3078,6 +3078,21 @@ EOF
   fi
 fi
 
+# We also need to know the API version because there was an
+# API change from 1.4.0 to 1.5.0.
+if test "$libiscsi" = "yes"; then
+  cat >$TMPC <<EOF
+#include <iscsi/iscsi.h>
+int main(void)
+{
+  iscsi_read10_task(0, 0, 0, 0, 0, 0, 0);
+  return 0;
+}
+EOF
+  if compile_prog "" "-liscsi"; then
+    libiscsi_version="1.4.0"
+  fi
+fi
 
 ##########################################
 # Do we need libm
@@ -3805,7 +3820,11 @@ echo "nss used          $smartcard_nss"
 echo "libusb            $libusb"
 echo "usb net redir     $usb_redir"
 echo "GLX support       $glx"
+if test "$libiscsi_version" = "1.4.0"; then
+echo "libiscsi support  $libiscsi (1.4.0)"
+else
 echo "libiscsi support  $libiscsi"
+fi
 echo "build guest agent $guest_agent"
 echo "QGA VSS support   $guest_agent_with_vss"
 echo "seccomp support   $seccomp"
@@ -4137,6 +4156,9 @@ fi
 
 if test "$libiscsi" = "yes" ; then
   echo "CONFIG_LIBISCSI=y" >> $config_host_mak
+  if test "$libiscsi_version" = "1.4.0"; then
+    echo "CONFIG_LIBISCSI_1_4=y" >> $config_host_mak
+  fi
 fi
 
 if test "$seccomp" = "yes"; then