science/antioch: Fix build with llvm16

Approved by:	portmgr (blanket)
Sponsored by:	The FreeBSD Foundation

science/antioch/Makefile

@@ -18,11 +18,12 @@ LIB_DEPENDS=	libgsl.so:math/gsl \
 		libOpenCL.so:devel/ocl-icd
 
 USES=		autoreconf compiler:c++11-lang eigen:3 gmake libtool localbase
+USE_CXXSTD=	c++11
 USE_GITHUB=	yes
 GH_ACCOUNT=	libantioch
-GNU_CONFIGURE=	yes
 USE_LDCONFIG=	yes
 
+GNU_CONFIGURE=	yes
 CONFIGURE_ARGS=	--disable-static \
 		--enable-eigen --with-eigen-include=${LOCALBASE}/include/eigen3 \
 		--enable-opencl \