diff --git Makefile.inc1 Makefile.inc1
index 0daa440..0f856fd 100644
--- Makefile.inc1
+++ Makefile.inc1
@@ -545,9 +545,11 @@ TARGET_ABI=	gnueabi
 .if defined(X_COMPILER_TYPE) && ${X_COMPILER_TYPE} == gcc
 # GCC requires -isystem and -L when using a cross-compiler.
 XCFLAGS+=	-isystem ${WORLDTMP}/usr/include -L${WORLDTMP}/usr/lib
+.if ${X_COMPILER_FEATURES:Mc++11}
 # Force using libc++ for external GCC.
 XCXXFLAGS+=	-isystem ${WORLDTMP}/usr/include/c++/v1 -std=c++11 \
 		-nostdinc++ -L${WORLDTMP}/../lib/libc++
+.endif	# ${X_COMPILER_FEATURES:Mc++11}
 .else
 TARGET_ABI?=	unknown
 TARGET_TRIPLE?=	${TARGET_ARCH:C/amd64/x86_64/}-${TARGET_ABI}-freebsd11.0
diff --git Makefile.libcompat Makefile.libcompat
index f0aafe6..31204e0 100644
--- Makefile.libcompat
+++ Makefile.libcompat
@@ -72,13 +72,20 @@ LIBCOMPATCFLAGS+=	${LIBCOMPATCPUFLAGS} \
 # -B is needed to find /usr/lib32/crti.o for GCC and /usr/libsoft/crti.o for
 # Clang/GCC.
 LIBCOMPATCFLAGS+=	-B${LIBCOMPATTMP}/usr/lib${libcompat}
+
+# External compiler needs
+.if ${MK_CROSS_COMPILER} == "no" || \
+    (${MK_CLANG_BOOTSTRAP} == "no" && ${MK_GCC_BOOTSTRAP} == "no")
 .if defined(X_COMPILER_TYPE) && ${X_COMPILER_TYPE} == gcc
 # GCC requires -isystem when using a cross-compiler.
 LIBCOMPATCFLAGS+=	-isystem ${LIBCOMPATTMP}/usr/include
+.if ${X_COMPILER_FEATURES:Mc++11}
 # Force using libc++ for external GCC.
 LIBCOMPATCXXFLAGS+=	-isystem ${LIBCOMPATTMP}/usr/include/c++/v1 -std=c++11 \
 			-nostdinc++ -L${LIBCOMPAT_OBJTREE}${.CURDIR}/lib/libc++
-.endif
+.endif	# ${X_COMPILER_FEATURES:Mc++11}
+.endif	# defined(X_COMPILER_TYPE) && ${X_COMPILER_TYPE} == gcc
+.endif	# External compiler
 
 # Yes, the flags are redundant.
 LIBCOMPATWMAKEENV+= MAKEOBJDIRPREFIX=${LIBCOMPAT_OBJTREE} \