diff --git a/mk/config.mk.in b/mk/config.mk.in
index a63d52b484dfd05de1edbde39ae1d4261b72b956..558bf4b9c4fc8876fdd8679f7c7537347de3a53c 100644
--- a/mk/config.mk.in
+++ b/mk/config.mk.in
@@ -86,7 +86,7 @@ HostVendor_CPP	                = @HostVendor_CPP@
 #
 LeadingUnderscore=@LeadingUnderscore@
 
-# Pin a suffix on executables? If so, what. (cygwin32 only).
+# Pin a suffix on executables? If so, what (Windows only).
 exeext=@exeext@
 
 ################################################################################
@@ -641,6 +641,12 @@ SGML2RTF		= $(DOCBOOK_PREFIX)db2rtf
 
 SGMLSTYLESHEET          = $(FPTOOLS_TOP_ABS)/docs/fptools-both.dsl
 
+# This may need to be changed by the user for local conditions
+SGML_TOP		= /usr/lib/sgml
+
+SGML_CATALOG_FILES	= ./catalog:$(SGML_TOP)/catalog:$(SGML_TOP)/docbook.cat:$(SGML_TOP)/stylesheets/docbook/catalog
+
+
 SRC_SGML2DVI_OPTS       = -d $(SGMLSTYLESHEET)
 SRC_SGML2HTML_OPTS      = -d $(SGMLSTYLESHEET)
 SRC_SGML2PS_OPTS      	= -d $(SGMLSTYLESHEET)