[libpeas] Fix cross references in docs

[Garrett Regier <gregier src gnome org>]

commit 62d0024bf3839ebe2665ac3019a57d66d097b592
Author: Garrett Regier <garrettregier gmail com>
Date:   Fri Dec 19 23:46:12 2014 -0800

    Fix cross references in docs
    
    This approach is copied from Gtk+.

 Makefile.am                |    6 +++++-
 configure.ac               |   15 +++++++++++++++
 docs/reference/Makefile.am |   11 +++++++++--
 3 files changed, 29 insertions(+), 3 deletions(-)
---
diff --git a/Makefile.am b/Makefile.am
index 9c96bf3..28674aa 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -1,6 +1,10 @@
 ## Process this file with automake to produce Makefile.in
 ACLOCAL_AMFLAGS = -I m4 ${ACLOCAL_FLAGS}
-DISTCHECK_CONFIGURE_FLAGS= --enable-gtk-doc --enable-glade-catalog
+
+DISTCHECK_CONFIGURE_FLAGS = \
+       --enable-glade-catalog          \
+       --enable-gtk-doc                \
+       --disable-doc-cross-references
 
 SUBDIRS = libpeas loaders
 GCOVDIRS = libpeas loaders
diff --git a/configure.ac b/configure.ac
index 42d9f5e..88c90c3 100644
--- a/configure.ac
+++ b/configure.ac
@@ -469,6 +469,21 @@ dnl ================================================================
 
 GTK_DOC_CHECK([1.11],[--flavour no-tmpl])
 
+AC_ARG_ENABLE(doc-cross-references,
+              AS_HELP_STRING([--disable-doc-cross-references],
+                             [cross reference symbols from other libraries @<:@default=yes@:>@]),
+              enable_doc_cross_references=$enableval,
+              enable_doc_cross_references=yes)
+
+AM_CONDITIONAL(ENABLE_DOC_CROSS_REFERENCES, test x$enable_doc_cross_references != xno)
+
+# Used to fix doc cross references
+GLIB_PREFIX="`$PKG_CONFIG --variable=prefix glib-2.0`"
+GTK_PREFIX="`$PKG_CONFIG --variable=prefix gtk+-3.0`"
+
+AC_SUBST(GLIB_PREFIX)
+AC_SUBST(GTK_PREFIX)
+
 dnl ================================================================
 dnl Libtool
 dnl ================================================================
diff --git a/docs/reference/Makefile.am b/docs/reference/Makefile.am
index a0c134c..45e3f90 100644
--- a/docs/reference/Makefile.am
+++ b/docs/reference/Makefile.am
@@ -30,9 +30,16 @@ MKDB_OPTIONS=--sgml-mode --output-format=xml
 # e.g. MKTMPL_OPTIONS=--only-section-tmpl
 MKTMPL_OPTIONS=
 
+if ENABLE_DOC_CROSS_REFERENCES
 # Extra options to supply to gtkdoc-fixref. Not normally needed.
 # e.g. FIXXREF_OPTIONS=--extra-dir=../gdk-pixbuf/html --extra-dir=../gdk/html
-FIXXREF_OPTIONS=
+FIXXREF_OPTIONS = \
+       --extra-dir=$(GLIB_PREFIX)/share/gtk-doc/html/glib      \
+       --extra-dir=$(GLIB_PREFIX)/share/gtk-doc/html/gmodule   \
+       --extra-dir=$(GLIB_PREFIX)/share/gtk-doc/html/gobject   \
+       --extra-dir=$(GLIB_PREFIX)/share/gtk-doc/html/gio       \
+       --extra-dir=$(GTK_PREFIX)/share/gtk-doc/html/gtk
+endif
 
 # Used for dependencies. The docs will be rebuilt if any of these change.
 HFILE_GLOB = \
@@ -44,7 +51,7 @@ CFILE_GLOB = \
        $(top_srcdir)/libpeas-gtk/*.c
 
 # Header files to ignore when scanning (These are internal to libpeas).
-IGNORE_HFILES=         \
+IGNORE_HFILES = \
        peas-debug.h                            \
        peas-dirs.h                             \
        peas-engine-priv.h                      \