diff --git a/tests/data/test018.param b/tests/data/test018.param
index 4afbdb3..072fa6b 100644
--- a/tests/data/test018.param
+++ b/tests/data/test018.param
@@ -1,5 +1,5 @@
 TITLE='Show GPS data on file'
 # Run in C locale to avoid errors when comparing numbers in output
-COMMAND='env LC_NUMERIC=C $PROGRAM -s "$STAGINGDIR/withgps.jpg" > "$OUTFILE" 2>&1'
+COMMAND='env XXXLC_NUMERIC=C $PROGRAM -s "$STAGINGDIR/withgps.jpg" > "$OUTFILE" 2>&1'
 RESULTCODE=0
 SEDCOMMAND='s@^.*/@@' # strip path