diff --git a/devel/rubygem-oj/Makefile b/devel/rubygem-oj/Makefile
index 367164535c29..795630834218 100644
--- a/devel/rubygem-oj/Makefile
+++ b/devel/rubygem-oj/Makefile
@@ -1,22 +1,22 @@
 PORTNAME=	oj
 PORTVERSION=	3.13.23
 PORTREVISION=	3
 CATEGORIES=	devel rubygems
 MASTER_SITES=	RG
 
 MAINTAINER=	sunpoet@FreeBSD.org
 COMMENT=	Fast JSON parser and serializer
 WWW=		https://www.ohler.com/oj/
 
 LICENSE=	MIT
 LICENSE_FILE=	${WRKSRC}/LICENSE
 
 USES=		gem
 
 # TODO: find a better way to do this
-# Copy all header file, as it is required by rubygem-oj-introspect
+# Install all header files, some of them are required by devel/rubygem-oj-introspect
 post-install:
-	${INSTALL} -d ${STAGEDIR}${PREFIX}/${GEMS_DIR}/${PORTNAME}-${PORTVERSION}/ext/oj
-	cd ${WRKSRC}/ext/oj && ${FIND} * -name "*.h" -type f -exec ${INSTALL_DATA} {} "${STAGEDIR}${PREFIX}/${GEMS_DIR}/${PORTNAME}-${PORTVERSION}/ext/oj/{}" \;
+	${MKDIR} ${STAGEDIR}${PREFIX}/${GEM_LIB_DIR}/ext/oj
+	${INSTALL_DATA} ${WRKSRC}/ext/oj/*.h ${STAGEDIR}${PREFIX}/${GEM_LIB_DIR}/ext/oj/
 
 .include <bsd.port.mk>