diff --git a/src/option.h b/src/option.h
index 0ad2fef..62e66cd 100644
--- a/src/option.h
+++ b/src/option.h
@@ -694,6 +694,9 @@
 #if defined(DYNAMIC_PYTHON)
 EXTERN char_u	*p_pydll;	/* 'pythondll' */
 #endif
+#if defined(FEAT_PYTHON) || defined(FEAT_PYTHON3)
+EXTERN long	p_pyx;		/* 'pyxversion' */
+#endif
 #ifdef FEAT_RELTIME
 EXTERN long	p_rdt;		/* 'redrawtime' */
 #endif