Index: comms/gnuradio/Makefile
===================================================================
--- comms/gnuradio/Makefile
+++ comms/gnuradio/Makefile
@@ -34,7 +34,11 @@
 		libgsl.so:${PORTSDIR}/math/gsl
 RUN_DEPENDS:=	${BUILD_DEPENDS}
 
-USES=		cmake:outsource iconv perl5 python:2.7 shebangfix
+# USES=compiler:c11 is necessary because base GCC fails:
+# volk/lib/volk_cpu.c: In function 'i_can_has_3dnow':
+# volk/lib/volk_cpu.c:62: error: can't find a register in class 'BREG' while reloading 'asm'
+# volk/lib/volk_cpu.c:62: error: 'asm' operand has impossible constraints
+USES=		cmake:outsource compiler:c11 iconv perl5 python:2.7 shebangfix
 SHEBANG_FILES=	grc/freedesktop/grc_setup_freedesktop.in
 CONFIGURE_ENV+=	LD_PRELOAD="${GCC_LIBS}/libstdc++.so:${GCC_LIBS}/libgcc_s.so.1"
 CMAKE_ARGS+=	-DSWIG_EXECUTABLE:STRING="${LOCALBASE}/bin/swig2.0"
@@ -46,7 +50,6 @@
 MAJOR_SUB_VER=	3.7.7
 DOCSDIR=	share/doc/${PORTNAME}-${MAJOR_SUB_VER}
 USE_GNOME=	pygtk2
-USE_GCC=	yes
 USE_WX=		3.0+
 USE_QT4=	gui xml qmake moc rcc uic
 WX_COMPS=	wx wx:build wx:run python:build python:run