docs: check for documentation generation tools in docs/configure.

It is sometimes hard to discover all the optional tools that should be
on a system to build all available Xen documentation. By checking for
documentation generation tools at ./configure time and displaying a
warning, Xen packagers will more easily learn about new optional build
dependencies, like markdown, when they are introduced.

Based on a patch by Matt Wilson. Changed to use a separate
docs/configure which is called from the top-level in the same manner
as stubdoms.

Rerun autogen.sh and "git add docs/configure" after applying this patch.

Signed-off-by: Matt Wilson <msw@amazon.com>
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Acked-by: Matt Wilson <msw@amazon.com>
  (For the change to introduce docs/configure)
Acked-by: Roger Pau Monné <roger.pau@citrix.com>
Committed-by: Ian Campbell <ian.campbell@citrix.com>

4 files changed, 69 insertions, 25 deletions

diff --git a/docs/Docs.mk b/docs/Docs.mk
deleted file mode 100644
index db3c19d81a..0000000000
--- a/docs/Docs.mk
+++ /dev/null
@@ -1,6 +0,0 @@
-FIG2DEV		:= fig2dev
-LATEX2HTML	:= latex2html
-POD2MAN		:= pod2man
-POD2HTML	:= pod2html
-POD2TEXT	:= pod2text
-MARKDOWN	:= markdown
diff --git a/docs/Makefile b/docs/Makefile
index 053d7af815..fdebae819a 100644
--- a/docs/Makefile
+++ b/docs/Makefile
@@ -2,7 +2,7 @@
 
 XEN_ROOT=$(CURDIR)/..
 include $(XEN_ROOT)/Config.mk
-include $(XEN_ROOT)/docs/Docs.mk
+-include $(XEN_ROOT)/config/Docs.mk
 
 VERSION		= xen-unstable
 
@@ -32,21 +32,27 @@ html: $(DOC_HTML) html/index.html
 
 .PHONY: txt
 txt:
-	@if which $(POD2TEXT) 1>/dev/null 2>/dev/null; then \
-	$(MAKE) $(DOC_TXT); else              \
-	echo "pod2text not installed; skipping text outputs."; fi
+ifdef POD2TEXT
+	$(MAKE) $(DOC_TXT)
+else
+	@echo "pod2text not installed; skipping text outputs."
+endif
 
 .PHONY: figs
 figs:
-	@set -e ; if which $(FIG2DEV) 1>/dev/null 2>/dev/null; then \
-	set -x; $(MAKE) -C figs ; else                   \
-	echo "fig2dev (transfig) not installed; skipping figs."; fi
+ifdef FIG2DEV
+	set -x; $(MAKE) -C figs
+else
+	@echo "fig2dev (transfig) not installed; skipping figs."
+endif
 
 .PHONY: man-pages
 man-pages:
-	@if which $(POD2MAN) 1>/dev/null 2>/dev/null; then \
-	$(MAKE) $(DOC_MAN1) $(DOC_MAN5); else              \
-	echo "pod2man not installed; skipping man-pages."; fi
+ifdef POD2MAN
+	$(MAKE) $(DOC_MAN1) $(DOC_MAN5)
+else
+	@echo "pod2man not installed; skipping man-pages."
+endif
 
 man1/%.1: man/%.pod.1 Makefile
 	$(INSTALL_DIR) $(@D)
@@ -69,6 +75,8 @@ clean:
 
 .PHONY: distclean
 distclean: clean
+	rm -rf ../config/Docs.mk config.log config.status config.cache \
+		autom4te.cache
 
 .PHONY: install
 install: all
@@ -84,30 +92,40 @@ html/index.html: $(DOC_HTML) ./gen-html-index INDEX
 	perl -w -- ./gen-html-index -i INDEX html $(DOC_HTML)
 
 html/%.html: %.markdown
-	@$(INSTALL_DIR) $(@D)
-	@set -e ; if which $(MARKDOWN) 1>/dev/null 2>/dev/null; then \
-	echo "Running markdown to generate $*.html ... "; \
+	$(INSTALL_DIR) $(@D)
+ifdef MARKDOWN
+	@echo "Running markdown to generate $*.html ... "
 	$(MARKDOWN) $< > $@.tmp ; \
-	$(call move-if-changed,$@.tmp,$@) ; else \
-	echo "markdown not installed; skipping $*.html."; fi
+	$(call move-if-changed,$@.tmp,$@)
+else
+	@echo "markdown not installed; skipping $*.html."
+endif
 
 html/%.txt: %.txt
-	@$(INSTALL_DIR) $(@D)
+	$(INSTALL_DIR) $(@D)
 	cp $< $@
 
 html/man/%.1.html: man/%.pod.1 Makefile
 	$(INSTALL_DIR) $(@D)
+ifdef POD2HTML
 	$(POD2HTML) --infile=$< --outfile=$@.tmp
 	$(call move-if-changed,$@.tmp,$@)
+else
+	@echo "pod2html not installed; skipping $<."
+endif
 
 html/man/%.5.html: man/%.pod.5 Makefile
 	$(INSTALL_DIR) $(@D)
+ifdef POD2HTML
 	$(POD2HTML) --infile=$< --outfile=$@.tmp
 	$(call move-if-changed,$@.tmp,$@)
+else
+	@echo "pod2html not installed; skipping $<."
+endif
 
 html/hypercall/index.html: ./xen-headers
 	rm -rf $(@D)
-	@$(INSTALL_DIR) $(@D)
+	$(INSTALL_DIR) $(@D)
 	./xen-headers -O $(@D) \
 		-T 'arch-x86_64 - Xen public headers' \
 		-X arch-ia64 -X arch-x86_32 -X xen-x86_32 -X arch-arm \
@@ -127,11 +145,23 @@ txt/%.txt: %.markdown
 
 txt/man/%.1.txt: man/%.pod.1 Makefile
 	$(INSTALL_DIR) $(@D)
+ifdef POD2TEXT
 	$(POD2TEXT) $< $@.tmp
 	$(call move-if-changed,$@.tmp,$@)
+else
+	@echo "pod2text not installed; skipping $<."
+endif
 
 txt/man/%.5.txt: man/%.pod.5 Makefile
 	$(INSTALL_DIR) $(@D)
+ifdef POD2TEXT
 	$(POD2TEXT) $< $@.tmp
 	$(call move-if-changed,$@.tmp,$@)
-
+else
+	@echo "pod2text not installed; skipping $<."
+endif
+
+ifeq (,$(findstring clean,$(MAKECMDGOALS)))
+$(XEN_ROOT)/config/Docs.mk:
+	$(error You have to run ./configure before building docs)
+endif
diff --git a/docs/configure.ac b/docs/configure.ac
new file mode 100644
index 0000000000..ea0552e43d
--- /dev/null
+++ b/docs/configure.ac
@@ -0,0 +1,20 @@
+#                                               -*- Autoconf -*-
+# Process this file with autoconf to produce a configure script.
+
+AC_PREREQ([2.67])
+AC_INIT([Xen Hypervisor Documentation], m4_esyscmd([../version.sh ../xen/Makefile]),
+    [xen-devel@lists.xen.org], [xen], [http://www.xen.org/])
+AC_CONFIG_SRCDIR([misc/xen-command-line.markdown])
+AC_CONFIG_FILES([../config/Docs.mk])
+AC_CONFIG_AUX_DIR([../])
+
+# M4 Macro includes
+m4_include([../m4/docs_tool.m4])
+
+AX_DOCS_TOOL_PROG([FIG2DEV], [fig2dev])
+AX_DOCS_TOOL_PROG([POD2MAN], [pod2man])
+AX_DOCS_TOOL_PROG([POD2HTML], [pod2html])
+AX_DOCS_TOOL_PROG([POD2TEXT], [pod2text])
+AX_DOCS_TOOL_PROGS([MARKDOWN], [markdown], [markdown markdown_py])
+
+AC_OUTPUT()
diff --git a/docs/figs/Makefile b/docs/figs/Makefile
index 5ecdae37fe..e128a4364f 100644
--- a/docs/figs/Makefile
+++ b/docs/figs/Makefile
@@ -1,7 +1,7 @@
 
 XEN_ROOT=$(CURDIR)/../..
 include $(XEN_ROOT)/Config.mk
-include $(XEN_ROOT)/docs/Docs.mk
+-include $(XEN_ROOT)/config/Docs.mk
 
 TARGETS= network-bridge.png network-basic.png