diff --git a/src/option.h b/src/option.h
index 8b982f5..b11316f 100644
--- a/src/option.h
+++ b/src/option.h
@@ -653,6 +653,7 @@
 EXTERN long	p_rdt;		/* 'redrawtime' */
 #endif
 EXTERN int	p_remap;	/* 'remap' */
+EXTERN long	p_re;		/* 'regexpengine' */
 EXTERN long	p_report;	/* 'report' */
 #if defined(FEAT_WINDOWS) && defined(FEAT_QUICKFIX)
 EXTERN long	p_pvh;		/* 'previewheight' */