[6.0] 3c3e37a22 look for sphinx-build during configure add --with-sphinx-build

[Dridi Boukelmoune]

commit 3c3e37a22a35c89fe0564ee3b7ee95e0c9bd06f3
Author: Nils Goroll <nils.goroll at uplex.de>
Date:   Tue Aug 21 09:19:16 2018 +0200

    look for sphinx-build during configure add --with-sphinx-build
    
    ... argument to specify a custom location
    
    Fixes #2742

diff --git a/configure.ac b/configure.ac
index 3fa117537..0c0266aae 100644
--- a/configure.ac
+++ b/configure.ac
@@ -46,6 +46,15 @@ if test "x$RST2MAN" = "xno"; then
     [rst2man is needed to build Varnish, please install python-docutils.])
 fi
 
+AC_ARG_WITH([sphinx-build],
+  AS_HELP_STRING([--with-sphinx-build=PATH], [Location of sphinx-build (auto)]),
+  [SPHINX="$withval"],
+  AC_CHECK_PROGS(SPHINX, [sphinx-build], [no]))
+if test "x$SPHINX" = "xno"; then
+  AC_MSG_ERROR(
+    [sphinx-build is needed to build Varnish, please install python-sphinx.])
+fi
+
 AC_ARG_WITH([rst2html],
                AS_HELP_STRING([--with-rst2html=PATH],
                               [Location of rst2html (auto)]),
diff --git a/doc/sphinx/Makefile.am b/doc/sphinx/Makefile.am
index f2d0df765..5eb2a1361 100644
--- a/doc/sphinx/Makefile.am
+++ b/doc/sphinx/Makefile.am
@@ -3,7 +3,7 @@
 
 # You can set these variables from the command line.
 SPHINXOPTS    =
-SPHINXBUILD   = sphinx-build -W -q -N
+SPHINXBUILD   = $(SPHINX) -W -q -N
 PAPER         = a4
 BUILDDIR      = $(builddir)/build