1.1 --- a/en/Makefile	Sun Jul 09 21:47:15 2006 -0700
     1.2 +++ b/en/Makefile	Tue Jul 11 23:48:25 2006 -0700
     1.3 @@ -6,6 +6,7 @@
     1.4  	00book.tex \
     1.5  	99book.bib \
     1.6  	99defs.tex \
     1.7 +	preface.tex \
     1.8  	intro.tex \
     1.9  	mq.tex \
    1.10  	build_id.tex
    1.11 @@ -38,6 +39,7 @@
    1.12  	cd $(dir $@) && makeindex $(basename $(notdir $@))
    1.13  	TEXINPUTS=$(dir $<): pdflatex $(call latex-options,$@) $< || (rm -f $@; exit 1)
    1.14  	TEXINPUTS=$(dir $<): pdflatex $(call latex-options,$@) $< || (rm -f $@; exit 1)
    1.15 +	if grep 'Reference.*undefined' $(@:.pdf=.log); then exit 1; fi
    1.16  endef
    1.17  
    1.18  pdf/hgbook.pdf: $(sources) $(image-sources:%.svg=%_pdf.png) examples