diff --git a/graphics/jp2a/Makefile b/graphics/jp2a/Makefile
index e445d8b75116..8d216e7f949a 100644
--- a/graphics/jp2a/Makefile
+++ b/graphics/jp2a/Makefile
@@ -17,6 +17,7 @@ LIB_DEPENDS=	libcurl.so:ftp/curl \
 		libpng16.so:graphics/png
 
 USES=		jpeg localbase ncurses pkgconfig tar:bz2
+USE_CSTD=	c99
 
 GNU_CONFIGURE=	yes