[gnome-doc-utils] Makefile.am: Fix gnome-doc-utils.m4 inclusion

[Marc-Antoine Perennou <marcop src gnome org>]

commit 67d8ef459e7a7e4b21b53d02704f77292cf017e0
Author: Quentin Glidic <sardemff7+git sardemff7 net>
Date:   Fri Oct 2 08:41:06 2015 +0200

    Makefile.am: Fix gnome-doc-utils.m4 inclusion
    
    GNOME_DOC_DEFINES is used in configure.ac, thus aclocal needs to know
    where to look for it.
    
    It used to work by using the *installed* version of gnome-doc-utils.m4,
    but for bootstrapping it fails. New features would be missing too.
    
    While at it, add ${ACLOCAL_FLAGS} as adviced by the Automake manual.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=755966
    
    Signed-off-by: Quentin Glidic <sardemff7+git sardemff7 net>

 Makefile.am |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/Makefile.am b/Makefile.am
index bc8702f..fb399cb 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -12,7 +12,7 @@ endif
 # doc must go last
 SUBDIRS = data po xslt tools $(build_SUBDIRS) doc
 
-ACLOCAL_AMFLAGS = -I m4
+ACLOCAL_AMFLAGS = -I m4 -I tools ${ACLOCAL_FLAGS}
 
 EXTRA_DIST =                                           \
        $(pkgdata_DATA)                                 \