doc: Warn about missing entries in htmlxref.cnf.

* doc/local.mk (AM_MAKEINFOHTMLFLAGS): New variable.

diff --git a/doc/local.mk b/doc/local.mk
index 51800bb..ed87638 100644 (file)
--- a/doc/local.mk
+++ b/doc/local.mk
@@ -122,6 +122,10 @@ dist_infoimage_DATA =                              \
   %D%/images/installer-partitions.png          \
   %D%/images/installer-resume.png
 
+# Ask for warnings about cross-referenced manuals that are not listed in
+# htmlxref.cnf.
+AM_MAKEINFOHTMLFLAGS = --set-customization-variable CHECK_HTMLXREF=true
+
 # Try hard to obtain an image size and aspect that's reasonable for inclusion
 # in an Info or PDF document.
 DOT_OPTIONS =                                  \