[gnome-online-accounts] build: Fix build when no Kerberos libraries are available

[Debarshi Ray <debarshir src gnome org>]

commit a50daa87406292c48698302d012978d16a1fa08b
Author: Philip Withnall <withnall endlessm com>
Date:   Mon Jul 31 17:11:00 2017 +0100

    build: Fix build when no Kerberos libraries are available
    
    If gnome-online-accounts is configured --enable-kerberos=auto (or
    unspecified), but no Kerberos libraries are available,
    enable_kerberos=auto and have_kerberos=no, but the configure code
    defines GOA_KERBEROS_ENABLED=1 anyway.
    
    Fallout from f8f1e79887d26530755f022e5b5e5af7222cb186
    
    https://bugzilla.gnome.org/show_bug.cgi?id=785649

 configure.ac |    6 ++++--
 1 files changed, 4 insertions(+), 2 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index 4cae16d..155ff9e 100644
--- a/configure.ac
+++ b/configure.ac
@@ -405,8 +405,10 @@ if test "$enable_kerberos" != "no"; then
 
   enable_kerberos=$have_kerberos
 
-  AC_DEFINE(GCR_API_SUBJECT_TO_CHANGE, 1, [Define to use the GCR API])
-  AC_DEFINE(GOA_KERBEROS_ENABLED, 1, [Enable Enterprise Identity data provider])
+  if test "$enable_kerberos" == "yes"; then
+    AC_DEFINE(GCR_API_SUBJECT_TO_CHANGE, 1, [Define to use the GCR API])
+    AC_DEFINE(GOA_KERBEROS_ENABLED, 1, [Enable Enterprise Identity data provider])
+  fi
 else
   enable_kerberos=no
 fi