reset upstream subtrees to yocto 2.6

Reset the following subtrees on thud HEAD:

  poky: 87e3a9739d
  meta-openembedded: 6094ae18c8
  meta-security: 31dc4e7532
  meta-raspberrypi: a48743dc36
  meta-xilinx: c42016e2e6

Also re-apply backports that didn't make it into thud:
  poky:
    17726d0 systemd-systemctl-native: handle Install wildcards

  meta-openembedded:
    4321a5d libtinyxml2: update to 7.0.1
    042f0a3 libcereal: Add native and nativesdk classes
    e23284f libcereal: Allow empty package
    030e8d4 rsyslog: curl-less build with fmhttp PACKAGECONFIG
    179a1b9 gtest: update to 1.8.1

Squashed OpenBMC subtree compatibility updates:
  meta-aspeed:
    Brad Bishop (1):
          aspeed: add yocto 2.6 compatibility

  meta-ibm:
    Brad Bishop (1):
          ibm: prepare for yocto 2.6

  meta-ingrasys:
    Brad Bishop (1):
          ingrasys: set layer compatibility to yocto 2.6

  meta-openpower:
    Brad Bishop (1):
          openpower: set layer compatibility to yocto 2.6

  meta-phosphor:
    Brad Bishop (3):
          phosphor: set layer compatibility to thud
          phosphor: libgpg-error: drop patches
          phosphor: react to fitimage artifact rename

    Ed Tanous (4):
          Dropbear: upgrade options for latest upgrade
          yocto2.6: update openssl options
          busybox: remove upstream watchdog patch
          systemd: Rebase CONFIG_CGROUP_BPF patch

Change-Id: I7b1fe71cca880d0372a82d94b5fd785323e3a9e7
Signed-off-by: Brad Bishop <bradleyb@fuzziesquirrel.com>
diff --git a/poky/scripts/lib/wic/plugins/source/bootimg-pcbios.py b/poky/scripts/lib/wic/plugins/source/bootimg-pcbios.py
index d599112..9347aa7 100644
--- a/poky/scripts/lib/wic/plugins/source/bootimg-pcbios.py
+++ b/poky/scripts/lib/wic/plugins/source/bootimg-pcbios.py
@@ -26,6 +26,7 @@
 
 import logging
 import os
+import re
 
 from wic import WicError
 from wic.engine import get_custom_config
@@ -47,10 +48,17 @@
         """
         Check if dirname exists in default bootimg_dir or in STAGING_DIR.
         """
-        for result in (bootimg_dir, get_bitbake_var("STAGING_DATADIR")):
+        staging_datadir = get_bitbake_var("STAGING_DATADIR")
+        for result in (bootimg_dir, staging_datadir):
             if os.path.exists("%s/%s" % (result, dirname)):
                 return result
 
+        # STAGING_DATADIR is expanded with MLPREFIX if multilib is enabled
+        # but dependency syslinux is still populated to original STAGING_DATADIR
+        nonarch_datadir = re.sub('/[^/]*recipe-sysroot', '/recipe-sysroot', staging_datadir)
+        if os.path.exists(os.path.join(nonarch_datadir, dirname)):
+            return nonarch_datadir
+
         raise WicError("Couldn't find correct bootimg_dir, exiting")
 
     @classmethod