[devhelp] docs: provide FIXXREF_OPTIONS for WebKitGTK+

[Sébastien Wilmet <swilmet src gnome org>]

commit 4880c265ac563dc3da08ab76085b46cea5664afa
Author: Sébastien Wilmet <swilmet gnome org>
Date:   Sun May 7 15:59:49 2017 +0200

    docs: provide FIXXREF_OPTIONS for WebKitGTK+
    
    On my system, without the FIXXREF_OPTIONS, it cannot find the link to
    WebKitWebView. Probably because I've not compiled WebKitGTK+ in jhbuild.

 configure.ac               |    4 ++++
 docs/reference/Makefile.am |    3 ++-
 2 files changed, 6 insertions(+), 1 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index c865934..5796486 100644
--- a/configure.ac
+++ b/configure.ac
@@ -88,9 +88,13 @@ AC_DEFINE_UNQUOTED(GETTEXT_PACKAGE,"$GETTEXT_PACKAGE", [Package name for gettext
 
 AM_PATH_PYTHON([2.3],[],[no])
 
+# GTK-Doc
 AX_REQUIRE_DEFINED([GTK_DOC_CHECK])
 GTK_DOC_CHECK([1.25],[--flavour no-tmpl])
 
+AX_REQUIRE_DEFINED([PKG_CHECK_VAR])
+PKG_CHECK_VAR([WEBKITGTK_PREFIX], [webkit2gtk-4.0], [prefix])
+
 AC_CONFIG_FILES([
        Makefile
        contrib/Makefile
diff --git a/docs/reference/Makefile.am b/docs/reference/Makefile.am
index f5c0610..89c5042 100644
--- a/docs/reference/Makefile.am
+++ b/docs/reference/Makefile.am
@@ -30,7 +30,8 @@ MKHTML_OPTIONS =
 
 # Extra options to supply to gtkdoc-fixref. Normally not needed.
 # e.g. FIXXREF_OPTIONS=--extra-dir=../gdk-pixbuf/html --extra-dir=../gdk/html
-FIXXREF_OPTIONS =
+FIXXREF_OPTIONS =                                                              \
+       --extra-dir=$(WEBKITGTK_PREFIX)/share/gtk-doc/html/webkit2gtk-4.0
 
 # Used for dependencies. The docs will be rebuilt if any of these change.
 # e.g. HFILE_GLOB=$(top_srcdir)/gtk/*.h