diff --git a/share/mk/doc.docbook.mk b/share/mk/doc.docbook.mk
index dd5b69d855..1117c206d3 100644
--- a/share/mk/doc.docbook.mk
+++ b/share/mk/doc.docbook.mk
@@ -174,14 +174,14 @@ XARGS?=		/usr/bin/xargs
 TEX?=		${PREFIX}/bin/tex
 PDFTEX?=	${PREFIX}/bin/pdftex
 TIDY?=		${PREFIX}/bin/tidy
-TIDYFLAGS?=	-i -m -f /dev/null
+TIDYOPTS?=	-i -m -f /dev/null ${TYDYFLAGS}
 HTML2TXT?=	${PREFIX}/bin/links
-HTML2TXTFLAGS?=	-dump
+HTML2TXTOPTS?=	-dump ${HTML2TXTFLAGS}
 HTML2PDB?=	${PREFIX}/bin/iSiloBSD
-HTML2PDBFLAGS?=	-y -d0 -Idef
+HTML2PDBOPTS?=	-y -d0 -Idef ${HTML2PDBFLAGS}
 DVIPS?=		${PREFIX}/bin/dvips
 .if defined(PAPERSIZE)
-DVIPSFLAGS?=	-t ${PAPERSIZE:L}
+DVIPSOPTS?=	-t ${PAPERSIZE:L} ${DVIPSFLAGS}
 .endif
 
 GZIP?=	-9
@@ -342,7 +342,7 @@ index.html HTML.manifest: ${SRCS} ${LOCAL_IMAGES_LIB} ${LOCAL_IMAGES_PNG} \
 	${JADE} -V html-manifest ${HTMLOPTS} -ioutput.html.images \
 		${JADEOPTS} -t sgml ${MASTERDOC}
 .if !defined(NO_TIDY)
-	-${TIDY} ${TIDYFLAGS} $$(${XARGS} < HTML.manifest)
+	-${TIDY} ${TIDYOPTS} $$(${XARGS} < HTML.manifest)
 .endif
 
 ${DOC}.html: ${SRCS} ${LOCAL_IMAGES_LIB} ${LOCAL_IMAGES_PNG} \
@@ -351,7 +351,7 @@ ${DOC}.html: ${SRCS} ${LOCAL_IMAGES_LIB} ${LOCAL_IMAGES_PNG} \
 		${JADEOPTS} -t sgml ${MASTERDOC} > ${.TARGET} || \
 		(${RM} -f ${.TARGET} && false)
 .if !defined(NO_TIDY)
-	-${TIDY} ${TIDYFLAGS} ${.TARGET}
+	-${TIDY} ${TIDYOPTS} ${.TARGET}
 .endif
 
 # Special target to produce HTML with no images in it.
@@ -371,10 +371,10 @@ ${DOC}.html.tar: ${DOC}.html ${LOCAL_IMAGES_LIB} \
 		${LOCAL_IMAGES_LIB} ${IMAGES_PNG} ${CSS_SHEET:T}
 
 ${DOC}.txt: ${DOC}.html-text
-	${HTML2TXT} ${HTML2TXTFLAGS} ${.ALLSRC} > ${.TARGET}
+	${HTML2TXT} ${HTML2TXTOPTS} ${.ALLSRC} > ${.TARGET}
 
 ${DOC}.pdb: ${DOC}.html ${LOCAL_IMAGES_LIB} ${LOCAL_IMAGES_PNG}
-	${HTML2PDB} ${HTML2PDBFLAGS} ${DOC}.html ${.TARGET}
+	${HTML2PDB} ${HTML2PDBOPTS} ${DOC}.html ${.TARGET}
 
 ${.CURDIR:T}.pdb: ${DOC}.pdb
 	${LN} -f ${.ALLSRC} ${.TARGET}
@@ -426,7 +426,7 @@ ${DOC}.pdf: ${DOC}.tex-pdf ${IMAGES_PDF}
 	${PDFTEX} "&pdfjadetex" '\nonstopmode\input{${DOC}.tex-pdf}'
 
 ${DOC}.ps: ${DOC}.dvi
-	${DVIPS} -o ${.TARGET} ${.ALLSRC}
+	${DVIPS} ${DVIPSOPTS} -o ${.TARGET} ${.ALLSRC}
 
 ${DOC}.tar: ${SRCS} ${LOCAL_IMAGES} ${LOCAL_CSS_SHEET}
 	${TAR} cf ${.TARGET} -C ${.CURDIR} ${SRCS} \
diff --git a/share/mk/doc.html.mk b/share/mk/doc.html.mk
index b89d7e1ab4..d2a715a4a2 100644
--- a/share/mk/doc.html.mk
+++ b/share/mk/doc.html.mk
@@ -68,11 +68,11 @@ TAR?=		/usr/bin/tar
 XARGS?=		/usr/bin/xargs
 
 TIDY?=		${PREFIX}/bin/tidy
-TIDYFLAGS?=	-i -m -f /dev/null
+TIDYOPTS?=	-i -m -f /dev/null ${TIDYFLAGS}
 HTML2TXT?=	${PREFIX}/bin/links
-HTML2TXTFLAGS?=	-dump
+HTML2TXTOPTS?=	-dump ${HTML2TXTFLAGS}
 HTML2PDB?=	${PREFIX}/bin/iSiloBSD
-HTML2PDBFLAGS?=	-y -d0 -Idef
+HTML2PDBOPTS?=	-y -d0 -Idef ${HTML2PDBFLAGS}
 
 GZIP?=	-9
 GZIP_CMD?=	gzip -qf ${GZIP}
@@ -150,14 +150,14 @@ all: ${_docs}
 ${DOC}.html: ${SRCS} ${LOCAL_IMAGES_LIB} ${LOCAL_IMAGES_PNG} ${LOCAL_CSS_SHEET}
 	${SGMLNORM} -c ${HTMLCATALOG} ${SRCS:S|^|${.CURDIR}/|} > ${.TARGET}
 .if !defined(NO_TIDY)
-	-${TIDY} ${TIDYFLAGS} ${.TARGET}
+	-${TIDY} ${TIDYOPTS} ${.TARGET}
 .endif
 
 ${DOC}.txt: ${DOC}.html
-	${HTML2TXT} ${HTML2TXTFLAGS} ${.ALLSRC} > ${.TARGET}
+	${HTML2TXT} ${HTML2TXTOPTS} ${.ALLSRC} > ${.TARGET}
 
 ${DOC}.pdb: ${DOC}.html ${LOCAL_IMAGES_LIB} ${LOCAL_IMAGES_PNG}
-	${HTML2PDB} ${HTML2PDBFLAGS} ${DOC}.html ${.TARGET}
+	${HTML2PDB} ${HTML2PDBOPTS} ${DOC}.html ${.TARGET}
 
 ${.CURDIR:T}.pdb: ${DOC}.pdb
 	${LN} -f ${.ALLSRC} ${.TARGET}
diff --git a/share/mk/doc.images.mk b/share/mk/doc.images.mk
index bad8674776..d77187ae8c 100644
--- a/share/mk/doc.images.mk
+++ b/share/mk/doc.images.mk
@@ -96,21 +96,25 @@ EPS2PNG_RES?= 100
 IMAGES_PDF=${IMAGES_GEN_PDF}
 
 SCR2PNG?=	${PREFIX}/bin/scr2png
+SCR2PNGOPTS?=	${SCR2PNGFLAGS}
 EPS2PNG?=	${PREFIX}/bin/peps
-EPS2PNGFLAGS?=	-p -r ${EPS2PNG_RES}
+EPS2PNGOPTS?=	-p -r ${EPS2PNG_RES} ${EPS2PNGFLAGS}
 PNGTOPNM?=	${PREFIX}/bin/pngtopnm
+PNGTOPNMOPTS?=	${PNGTOPNMFLAGS}
 PNMTOPS?=	${PREFIX}/bin/pnmtops
-PNMTOPSFLAGS?=	-noturn
+PNMTOPSOPTS?=	-noturn ${PNMTOPSFLAGS}
 EPSTOPDF?=	${PREFIX}/bin/epstopdf
+EPSTOPDFOPTS?=	${EPSTOPDFFLAGS}
 
 # Use suffix rules to convert .scr files to .png files
 .SUFFIXES:	.scr .png .eps
 
 .scr.png:
-	${SCR2PNG} < ${.IMPSRC} > ${.TARGET}
+	${SCR2PNG} ${SCR2PNGOPTS} < ${.IMPSRC} > ${.TARGET}
 .scr.eps:
-	${SCR2PNG} < ${.ALLSRC} | ${PNGTOPNM} | \
-		${PNMTOPS} ${PNMTOPSFLAGS} > ${.TARGET}
+	${SCR2PNG} ${SCR2PNGOPTS} < ${.ALLSRC} | \
+		${PNGTOPNM} ${PNGTOPNMOPTS} | \
+		${PNMTOPS} ${PNMTOPSOPTS} > ${.TARGET}
 
 # We can't use suffix rules to generate the rules to convert EPS to PNG and
 # PNG to EPS.  This is because a .png file can depend on a .eps file, and
@@ -119,17 +123,19 @@ EPSTOPDF?=	${PREFIX}/bin/epstopdf
 
 .for _curimage in ${IMAGES_GEN_PNG}
 ${_curimage}: ${_curimage:S/.png$/.eps/}
-	${EPS2PNG} ${EPS2PNGFLAGS} -o ${.TARGET} ${.ALLSRC}
+	${EPS2PNG} ${EPS2PNGOPTS} -o ${.TARGET} ${.ALLSRC}
 .endfor
 
 .for _curimage in ${IMAGES_GEN_EPS}
 ${_curimage}: ${_curimage:S/.eps$/.png/}
-	${PNGTOPNM} ${.ALLSRC} | ${PNMTOPS} ${PNMTOPSFLAGS} > ${.TARGET}
+	${PNGTOPNM} ${PNGTOPNMOPTS} ${.ALLSRC} | \
+		${PNMTOPS} ${PNMTOPSOPTS} > ${.TARGET}
 .endfor
 
 .for _curimage in ${IMAGES_GEN_PDF}
 ${_curimage}: ${_curimage:S/.pdf$/.eps/}
-	${EPSTOPDF} --outfile=${.TARGET} ${.CURDIR}/${_curimage:S/.pdf$/.eps/}
+	${EPSTOPDF} ${EPSTOPDFOPTS} --outfile=${.TARGET} \
+		${.CURDIR}/${_curimage:S/.pdf$/.eps/}
 .endfor
 
 .if ${.OBJDIR} != ${.CURDIR}
diff --git a/share/mk/doc.subdir.mk b/share/mk/doc.subdir.mk
index 0f291fe3af..c2eb899499 100644
--- a/share/mk/doc.subdir.mk
+++ b/share/mk/doc.subdir.mk
@@ -47,9 +47,12 @@
 #			Remove the object directory, if any.
 #
 
+.if !target(__initialized__)
+__initialized__:
 .if exists(${.CURDIR}/../Makefile.inc)
 .include "${.CURDIR}/../Makefile.inc"
 .endif
+.endif
 
 .if !target(install)
 install: afterinstall symlinks