[gtk-doc] test: fix out-of-srcdir tests

[Stefan Kost <stefkost src gnome org>]

commit 24563bef055333c6596ea58848e15c69ade68250
Author: Stefan Sauer <ensonic users sf net>
Date:   Sun May 17 10:50:21 2015 +0200

    test: fix out-of-srcdir tests
    
    Locate devhelp2.xsd via abs_top_srcdir.

 tests/sanity.sh |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/tests/sanity.sh b/tests/sanity.sh
index 3b3a92a..6b03bf9 100755
--- a/tests/sanity.sh
+++ b/tests/sanity.sh
@@ -80,7 +80,7 @@ tested=`expr $tested + 1`
 # check validity of devhelp2 files
 nok=0
 for file in $dir/*/docs*/html/*.devhelp2; do
-  xmllint --noout --nonet --schema $SRCDIR/../devhelp2.xsd $file
+  xmllint --noout --nonet --schema $ABS_TOP_SRCDIR/devhelp2.xsd $file
   if test $? != 0 ; then
     echo 1>&2 "devhelp2 xml validity check failed for $file"
     nok=`expr $nok + 1`;