From 5ba958829f73ecc02658a46f5b1bba5ffed2281d Mon Sep 17 00:00:00 2001
From: rofl0r <rofl0r@users.noreply.github.com>
Date: Wed, 12 Aug 2020 00:15:45 +0100
Subject: [PATCH] add configure option to disable manpage generation

using --disable-manpage-support it's finally possibly to disable
the formerly obligatory use of a2x to generate the manpage
documentation.

this is the final solution to the decade old problem that users need
to install the enormous asciidoc package to compile TINYproxy from
source, or otherwise get a build error, even though the vast majority
is only interested in the program itself.

solution was inspired by PR #179.

closes #179
closes #111

note that since 1.10.0 release the generated release tarball includes
the generated manpages too; in which case neither the use of a2x
nor --disable-manpage-support is required.
---
 configure.ac          | 33 +++++++++++++++++++++++++++------
 docs/man5/Makefile.am |  2 ++
 docs/man8/Makefile.am |  2 ++
 3 files changed, 31 insertions(+), 6 deletions(-)

diff --git a/configure.ac b/configure.ac
index 9623754..e645dc1 100644
--- a/configure.ac
+++ b/configure.ac
@@ -96,6 +96,15 @@ if test x"$transparent_enabled" = x"yes"; then
    AC_DEFINE(TRANSPARENT_PROXY)
 fi
 
+dnl Let user decide whether he wants support for manpages
+dnl Which require either a2x/asciidoctor or a tarball release
+AH_TEMPLATE([MANPAGE_SUPPORT],
+	    [Build manpages with a2x/asciidoctor if they are missing from the distribution.])
+TP_ARG_ENABLE(manpage_support,
+              [Enable support for building manpages (default is YES)],
+              yes)
+AM_CONDITIONAL(HAVE_MANPAGE_INTEREST, test x"$manpage_support_enabled" = x"yes")
+
 # This is required to build test programs below
 AC_PROG_CC
 
@@ -173,15 +182,14 @@ AC_SUBST(CPPFLAGS)
 AC_SUBST(LIBS)
 AC_SUBST(ADDITIONAL_OBJECTS)
 
+if test x"$manpage_support_enabled" = x"yes"; then
 # Check for asciidoc
 AC_PATH_PROG(A2X, a2x, no)
-AM_CONDITIONAL(HAVE_A2X, test "x$A2X" != "xno")
-
+if test "x$A2X" = "xno" ; then
 # Check for asciidoctor
 AC_PATH_PROG(ASCIIDOCTOR, asciidoctor, no)
-AM_CONDITIONAL(HAVE_ASCIIDOCTOR, test "x$ASCIIDOCTOR" != "xno")
-
-# checking xmllint
+else
+# checking xmllint, which is only used together with a2x
 AC_PATH_PROG(XMLLINT, xmllint, no)
 if test "x$XMLLINT" != "xno"; then
   AS_ECHO_N("testing xmllint... ")
@@ -194,7 +202,20 @@ if test "x$XMLLINT" != "xno"; then
   fi
   rm -f conftest.txt conftest.xml
 fi
-AM_CONDITIONAL(HAVE_XMLLINT, test "x$XMLLINT" != "xno")
+fi #a2x installed
+
+if test "x$A2X" = "xno" -a "x$ASCIIDOCTOR" = "xno" && \
+ ! test -e docs/man5/tinyproxy.conf.5 -a -e docs/man8/tinyproxy.8 ; then
+AC_MSG_ERROR([
+  manpage generation requested, but neither a2x, asciidoctor
+  nor pre-generated manpages found.
+  Use --disable-manpage-support if you want to compile anyway.])
+fi
+fi #manpage_support_enabled
+
+AM_CONDITIONAL(HAVE_A2X, test "x$A2X" != "x" -a "x$A2X" != "xno")
+AM_CONDITIONAL(HAVE_XMLLINT, test "x$XMLLINT" != "x" -a "x$XMLLINT" != "xno")
+AM_CONDITIONAL(HAVE_ASCIIDOCTOR, test "x$ASCIIDOCTOR" != "x" -a "x$ASCIIDOCTOR" != "xno")
 
 AC_CONFIG_FILES([
 Makefile
diff --git a/docs/man5/Makefile.am b/docs/man5/Makefile.am
index 0428e51..3447ad2 100644
--- a/docs/man5/Makefile.am
+++ b/docs/man5/Makefile.am
@@ -1,5 +1,7 @@
+if HAVE_MANPAGE_INTEREST
 MAN5_FILES  = \
 	tinyproxy.conf.txt
+endif
 
 if HAVE_XMLLINT
 A2X_ARGS = -d manpage -f manpage
diff --git a/docs/man8/Makefile.am b/docs/man8/Makefile.am
index bf2c09c..0d1eda1 100644
--- a/docs/man8/Makefile.am
+++ b/docs/man8/Makefile.am
@@ -1,5 +1,7 @@
+if HAVE_MANPAGE_INTEREST
 MAN8_FILES = \
 	tinyproxy.txt
+endif
 
 if HAVE_XMLLINT
 A2X_ARGS = -d manpage -f manpage