Taken from the ArchLinux folks.

--- poppler.defs	2009-09-27 16:07:59.000000000 +0700
+++ poppler.defs	2015-12-22 16:36:14.000000000 +0600
@@ -579,16 +579,4 @@
 )
 
-(define-enum Orientation
-  (in-module "Poppler")
-  (c-name "PopplerOrientation")
-  (gtype-id "POPPLER_TYPE_ORIENTATION")
-  (values
-    '("portrait" "POPPLER_ORIENTATION_PORTRAIT")
-    '("landscape" "POPPLER_ORIENTATION_LANDSCAPE")
-    '("upsidedown" "POPPLER_ORIENTATION_UPSIDEDOWN")
-    '("seascape" "POPPLER_ORIENTATION_SEASCAPE")
-  )
-)
-
 (define-enum PageTransitionType
   (in-module "Poppler")