[sfnt] Don't add instances to non-variation fonts.

* src/sfnt/sfobjs.c (sfnt_init_face): Fix it.

ChangeLog

@@ -1,3 +1,9 @@
+2017-03-20  Werner Lemberg  <wl@gnu.org>
+
+	[sfnt] Don't add instances to non-variation fonts.
+
+	* src/sfnt/sfobjs.c (sfnt_init_face): Fix it.
+
 2017-03-20  Werner Lemberg  <wl@gnu.org>
 
 	* src/cff/cffgload.c (cff_builder_init): Add safety guard (#50578).

src/sfnt/sfobjs.c

@@ -1012,8 +1012,9 @@
        *  later on.  Here, we have to adjust `num_instances' accordingly.
        */
 
-      if ( !( FT_ALLOC( default_values, num_axes * 2 )  ||
-              FT_ALLOC( instance_values, num_axes * 2 ) ) )
+      if ( ( face->variation_support & TT_FACE_FLAG_VAR_FVAR ) &&
+           !( FT_ALLOC( default_values, num_axes * 2 )  ||
+              FT_ALLOC( instance_values, num_axes * 2 ) )      )
       {
         /* the current stream position is 16 bytes after the table start */
         FT_ULong  array_start = FT_STREAM_POS() - 16 + offset;