From b9986739f0ec0ffc2bf37951fc8308fbfb433d0c Mon Sep 17 00:00:00 2001
From: Florian Westphal <fw@strlen.de>
Date: Sat, 6 Jun 2020 16:14:44 +0200
Subject: [PATCH] configure: add --with/without-doxygen switch

Allows to turn off doxygen even if its installed, via
--without-doxygen.

Default is to probe for doxygen presence (--with-doxygen).

Signed-off-by: Florian Westphal <fw@strlen.de>
(cherry picked from commit 3622e6061d5cc34db70cef7b8516217e27ffa57c)

Conflicts:
- Change configure script itself instead of configure.ac as original patch
  does.
---

--- a/configure
+++ b/configure
@@ -770,6 +770,7 @@
 with_gnu_ld
 with_sysroot
 enable_libtool_lock
+with_doxygen
 '
       ac_precious_vars='build_alias
 host_alias
@@ -1441,6 +1442,7 @@
   --with-gnu-ld           assume the C compiler uses GNU ld [default=no]
   --with-sysroot[=DIR]    Search for dependent libraries within DIR (or the
                           compiler's sysroot if not specified).
+  --with-doxygen          create doxygen documentation
 
 Some influential environment variables:
   CC          C compiler command
@@ -13278,7 +13280,17 @@
 
 
 
-for ac_prog in doxygen
+# Check whether --with-doxygen was given.
+if test "${with_doxygen+set}" = set; then :
+  withval=$with_doxygen; with_doxygen="$withval"
+else
+  with_doxygen=yes
+fi
+
+
+if test "x$with_doxygen" != xno; then :
+
+	for ac_prog in doxygen
 do
   # Extract the first word of "$ac_prog", so it can be a program name with args.
 set dummy $ac_prog; ac_word=$2
@@ -13320,9 +13332,7 @@
   test -n "$DOXYGEN" && break
 done
 
-if test -z "$DOXYGEN";
-	then { $as_echo "$as_me:${as_lineno-$LINENO}: WARNING: Doxygen not found - continuing without Doxygen support" >&5
-$as_echo "$as_me: WARNING: Doxygen not found - continuing without Doxygen support" >&2;}
+
 fi
 
  if test -n "$DOXYGEN"; then
@@ -13333,6 +13343,10 @@
   HAVE_DOXYGEN_FALSE=
 fi
 
+if test -z "$DOXYGEN"; then
+		{ $as_echo "$as_me:${as_lineno-$LINENO}: WARNING: Doxygen not found - continuing without Doxygen support" >&5
+$as_echo "$as_me: WARNING: Doxygen not found - continuing without Doxygen support" >&2;}
+fi
 cat >confcache <<\_ACEOF
 # This file is a shell script that caches the results of configure
 # tests run on this system so they can be shared between configure