diff --git a/Makefile b/Makefile
index 9e5b739..3e5b8dd 100644
--- a/Makefile
+++ b/Makefile
@@ -19,6 +19,7 @@ PATH_DOC_CSS=${PATH_DOC}/manual.css
 PATH_DOC_IMG=${PATH_DOC}/img
 PATH_MANUAL_TEXI=${PATH_DOC}/manual.texi
 
+doc_src := $(wildcard $(PATH_DOC)/*.texi)
 doc_imgs := $(patsubst %.dia, %.png, $(wildcard $(PATH_DOC_IMG)/*.dia))
 
 COMBINE=${PATH_TOOLS}/combine
@@ -39,8 +40,9 @@ all:     combine doc
 # create build dir
 mkbuild:
 	mkdir -p "$(PATH_BUILD)"
-mkbuild-doc:
+$(PATH_DOC_OUTPUT):
 	mkdir -p "$(PATH_DOC_OUTPUT)"
+mkbuild-doc: | $(PATH_DOC_OUTPUT)
 
 # combine all modules into easily redistributable ease.js file (intended for
 # browser)
@@ -65,15 +67,15 @@ perf-%.js: default
 # generate texinfo documentation (twice to generate TOC), then remove the extra
 # files that were generated
 #
-# generates: pdf, HTML (multiple pages), HTML (single page)
-doc: doc-pdf doc-texi doc-plain doc-html
-
-doc-img: $(doc_imgs)
+# generates: pdf, info, HTML (multiple pages), HTML (single page)
+doc: | doc-pdf doc-info doc-plain doc-html
 
+# doc images
 doc/img/%.png: doc/img/%.dia
 	dia -e $@ -s 600x $<
 
-doc-pdf: | mkbuild-doc doc-img
+# doc pdf
+$(PATH_DOC_OUTPUT)/%.pdf: $(doc_src) | mkbuild-doc doc-img
 	TEXINPUTS="$(PATH_DOC):" \
 		pdftex -output-directory "${PATH_DOC}" "${PATH_MANUAL_TEXI}" && \
 		TEXINPUTS="$(PATH_DOC):" \
@@ -81,23 +83,37 @@ doc-pdf: | mkbuild-doc doc-img
 	mv -f "${PATH_DOC}"/*.pdf "${PATH_DOC_OUTPUT}"
 	cd "$(PATH_DOC)" && rm -f $(shell cat "$(PATH_DOC)/.gitignore")
 
-doc-texi: | mkbuild-doc
-	makeinfo -I "$(PATH_DOC)" -o "${PATH_DOC_OUTPUT_INFO}" \
-		"${PATH_MANUAL_TEXI}";
+# doc info
+$(PATH_DOC_OUTPUT_INFO): $(doc_src) | mkbuild-doc
+	makeinfo -I "$(PATH_DOC)" -o $@ "$(PATH_MANUAL_TEXI)";
 
-doc-plain: | mkbuild-doc
-	makeinfo --plain -I "$(PATH_DOC)" "${PATH_MANUAL_TEXI}" \
-		> "${PATH_DOC_OUTPUT_PLAIN}";
+# doc plain text
+$(PATH_DOC_OUTPUT_PLAIN): | mkbuild-doc
+	makeinfo --plain -I "$(PATH_DOC)" "${PATH_MANUAL_TEXI}" > $@
 
-doc-html: | mkbuild-doc doc-img
+# doc html (multiple pages)
+$(PATH_DOC_OUTPUT_HTML)/index.html: | $(PATH_DOC_OUTPUT_HTML)/img mkbuild-doc doc-img
 	makeinfo --html --css-include="${PATH_DOC_CSS}" \
-		-I "$(PATH_DOC)" -o "${PATH_DOC_OUTPUT_HTML}" "${PATH_MANUAL_TEXI}"; \
+		-I "$(PATH_DOC)" -o "${PATH_DOC_OUTPUT_HTML}" "${PATH_MANUAL_TEXI}";
+
+# doc html (single page)
+$(PATH_DOC_OUTPUT_HTML1): | $(PATH_DOC_OUTPUT)/img mkbuild-doc doc-img
 	makeinfo --no-split --html --css-include="${PATH_DOC_CSS}" \
 		-I "$(PATH_DOC)" -o "${PATH_DOC_OUTPUT_HTML1}" "${PATH_MANUAL_TEXI}";
-	mkdir -p "$(PATH_DOC_OUTPUT_HTML)/img"
-	cp "$(PATH_DOC_IMG)"/*.png "$(PATH_DOC_OUTPUT_HTML)/img"
-	ln -s manual/img "$(PATH_DOC_OUTPUT)/img"
 
+# doc images (in build dir)
+$(PATH_DOC_OUTPUT)/img: | mkbuild-doc doc-img
+	mkdir -p $@
+	cp "$(PATH_DOC_IMG)"/*.png $@
+$(PATH_DOC_OUTPUT_HTML)/img: $(PATH_DOC_OUTPUT)/img
+	mkdir -p $(PATH_DOC_OUTPUT_HTML)
+	ln -s ../img $@
+
+doc-img: $(doc_imgs)
+doc-pdf: $(PATH_DOC_OUTPUT)/manual.pdf
+doc-info: $(PATH_DOC_OUTPUT_INFO)
+doc-plain: $(PATH_DOC_OUTPUT_PLAIN)
+doc-html: $(PATH_DOC_OUTPUT_HTML)/index.html $(PATH_DOC_OUTPUT_HTML1)
 
 # clean up build dir
 clean: