poky-sanity.bbclass: bblayers.conf should be updated automatically

- we need a bbclass (poky-sanity) so that we can append to the
check_bblayers_conf bitbake function from sanity.bbclass the
bblayers.conf specific merging functionality
- add check_bblayers_conf_append bitbake function which does the
meta-yocto specific updates (the bblayers.conf v5 -> v6 update)
- every layer should make its specific bblayers.conf updates
- we ask the user to re-run bitbake because we can't trigger
reparsing without being invasive

[YOCTO #3082]

(From meta-yocto rev: 636783633ac0cd5bf66f8b9c9b26cb31ad082451)

Signed-off-by: Constantin Musca <constantinx.musca@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta-yocto/classes/poky-sanity.bbclass

@@ -0,0 +1,16 @@
+python check_bblayers_conf_append() {
+    if current_lconf != lconf_version:
+        if current_lconf == 5:
+            index, meta_yocto_line = find_line('meta-yocto\s*\\\\\\n', lines)
+            if meta_yocto_line:
+                lines.insert(index + 1, meta_yocto_line.replace('meta-yocto',
+                                                                'meta-yocto-bsp'))
+            else:
+                sys.exit()
+
+            index, line = find_line('LCONF_VERSION', lines)
+            current_lconf += 1
+            lines[index] = 'LCONF_VERSION = "%d"\n' % current_lconf
+            with open(bblayers_fn, "w") as f:
+                f.write(''.join(lines))
+}

meta-yocto/conf/distro/poky.conf

@@ -98,6 +98,9 @@ BB_SIGNATURE_HANDLER ?= 'OEBasicHash'
 #
 OELAYOUT_ABI = "8"
 
+# add poky sanity bbclass
+INHERIT += "poky-sanity"
+
 #WARN_QA = "unsafe-references-in-binaries unsafe-references-in-scripts"
 WARN_QA = ""
 ERROR_QA = "dev-so debug-deps dev-deps debug-files arch la2 pkgconfig la perms useless-rpaths rpaths staticdev ldflags"