[folks] Reduce libebook dependency when not compiling the BlueZ backend

[Travis Reitter <treitter src gnome org>]

commit da4544b9cf2a10d8d060bf8ed3e09a12006b80e8
Author: Simon McVittie <simon mcvittie collabora co uk>
Date:   Mon Mar 24 09:45:01 2014 +0000

    Reduce libebook dependency when not compiling the BlueZ backend
    
    Debian unstable is currently stuck with Evolution 3.8, due to the
    number of ABI transitions required to get from here to there. Folks
    does not appear to need a newer version if the optional BlueZ backend
    is not installed, and Debian doesn't currently enable that backend
    anyway.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=726980

 configure.ac |    5 ++++-
 1 files changed, 4 insertions(+), 1 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index 729e971..f1ae847 100644
--- a/configure.ac
+++ b/configure.ac
@@ -263,7 +263,8 @@ VALA_REQUIRED=0.22.0.28-9090
 VALADOC_REQUIRED=0.3.1
 TRACKER_SPARQL_MAJOR=0.16
 TRACKER_SPARQL_REQUIRED=0.15.2
-EBOOK_REQUIRED=3.9.1
+EBOOK_REQUIRED=3.8
+EBOOK_REQUIRED_FOR_BLUEZ=3.9.1
 EDATASERVER_REQUIRED=3.5.3.1
 ZEITGEIST_REQUIRED=0.9.14
 GEE_REQUIRED=0.8.4
@@ -324,6 +325,8 @@ AS_IF([test x$enable_tracker_backend = xyes], [
                            $TRACKER_SPARQL_REQUIRED])
 ])
 
+AS_IF([test x$enable_bluez_backend = xyes], [EBOOK_REQUIRED=$EBOOK_REQUIRED_FOR_BLUEZ])
+
 AS_IF([test x$enable_eds_backend = xyes], [
         PKG_CHECK_MODULES([EBOOK], [libebook-1.2 >= $EBOOK_REQUIRED
                                     libebook-contacts-1.2 >= $EBOOK_REQUIRED])