diff --git a/make-includes/local_configuration.make.in b/make-includes/local_configuration.make.in
index 4d4cb07..8c2f238 100755
--- a/make-includes/local_configuration.make.in
+++ b/make-includes/local_configuration.make.in
@@ -1,4 +1,13 @@
+################################################################################
+#
 # @configure_input@
+#
+# This file sets up items that are system dependent (mostly paths to various)
+# tools, so it must always be loaded FIRST, before any other make includes! In
+# particular, it MUST be loaded before files that assume its existence, such
+# as standard_rules.make.
+#
+################################################################################
 
 # File system.
 MKDIR=@MKDIR_P@
@@ -35,7 +44,7 @@
 
 # XML manipulation.
 XMLLINT=@XMLLINT@
-XSLTPROC=@XSLTPROC@
+XSLTPROC=@XSLTPROC@ # Note: distinct from the XSLT environment variable.
 
 # Image manipulation and conversion (includes PDF & PS).
 CONVERT=@CONVERT@