Documentation: Fix man page breakage with DocBook XSL v1.72

diff --git a/Makefile b/Makefile
index 2331e45adfb09c7327d5868f536bc5d413d8af95..41c90ad1d49c92829cd678f5f4ce8ad9f2e05985 100644 (file)
--- a/Makefile
+++ b/Makefile
@@ -109,6 +109,8 @@ all::
 #
 # Define ASCIIDOC8 if you want to format documentation with AsciiDoc 8
 #
+# Define DOCBOOK_XSL_172 if you want to format man pages with DocBook XSL v1.72.
+#
 # Define NO_PERL_MAKEMAKER if you cannot use Makefiles generated by perl's
 # MakeMaker (e.g. using ActiveState under Cygwin).
 #