buildhistory: write the contents of the sysroot

Changes to the sysroot are just as interesting during development, so write the
file listing for the sysroot to buildhistory too.

(From OE-Core rev: b3ac82a27ab70ed6996fe3087a578ac637820329)

Signed-off-by: Ross Burton <ross.burton@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/classes/buildhistory.bbclass

@@ -60,15 +60,23 @@ SSTATEPOSTUNPACKFUNCS[vardepvalueexclude] .= "| buildhistory_emit_outputsigs"
 # When extending build history, derive your class from buildhistory.bbclass
 # and extend this list here with the additional files created by the derived
 # class.
-BUILDHISTORY_PRESERVE = "latest latest_srcrev"
+BUILDHISTORY_PRESERVE = "latest latest_srcrev sysroot"
 
 PATCH_GIT_USER_EMAIL ?= "buildhistory@oe"
 PATCH_GIT_USER_NAME ?= "OpenEmbedded"
 
+buildhistory_emit_sysroot() {
+	mkdir --parents ${BUILDHISTORY_DIR_PACKAGE}
+	buildhistory_list_files ${SYSROOT_DESTDIR} ${BUILDHISTORY_DIR_PACKAGE}/sysroot
+}
+
 #
 # Write out metadata about this package for comparison when writing future packages
 #
 python buildhistory_emit_pkghistory() {
+    if d.getVar('BB_CURRENTTASK') in ['populate_sysroot', 'populate_sysroot_setscene']:
+        bb.build.exec_func("buildhistory_emit_sysroot", d)
+
     if not d.getVar('BB_CURRENTTASK') in ['packagedata', 'packagedata_setscene']:
         return 0