XDEV fix

[Shankar Giri Venkita Giri]

XDEV has been broken for a while in FreeBSD 11. As of today, I had to perform minimal patches to get it to build successfully. Can someone review this and try it out to make sure?
Also clang being a native cross-compiler, I was wondering if XDEV had specific advantages.
 
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diff --git a/lib/libc++/Makefile b/lib/libc++/Makefile
index 6e70cf1..ec7725d 100644
--- a/lib/libc++/Makefile
+++ b/lib/libc++/Makefile
@@ -4,6 +4,7 @@
 PACKAGE=    clibs
 _LIBCXXRTDIR=    ${.CURDIR}/../../contrib/libcxxrt
+_LIBCXXDIR=    ${.CURDIR}/../../contrib/libc++
 HDRDIR=        ${.CURDIR}/../../contrib/libc++/include
 SRCDIR=        ${.CURDIR}/../../contrib/libc++/src
 CXXINCLUDEDIR=    ${INCLUDEDIR}/c++/v${SHLIB_MAJOR}
@@ -63,7 +64,7 @@ cxxrt_${_S}: ${_LIBCXXRTDIR}/${_S} .NOMETA
 .endfor
 WARNS=        0
-CFLAGS+=    -isystem ${HDRDIR} -isystem ${_LIBCXXRTDIR} -nostdinc++ -nostdlib -DLIBCXXRT
+CFLAGS+=    -isystem ${_LIBCXXDIR} -isystem ${_LIBCXXRTDIR} -nostdinc++ -nostdlib -DLIBCXXRT -I${HDRDIR}
 .if empty(CXXFLAGS:M-std=*)
 CXXFLAGS+=    -std=c++11
 .endif
diff --git a/lib/libdevdctl/Makefile b/lib/libdevdctl/Makefile
index 5a18a14..963f906 100644
--- a/lib/libdevdctl/Makefile
+++ b/lib/libdevdctl/Makefile
@@ -1,6 +1,9 @@
 # $FreeBSD$
 LIB_CXX=    devdctl
+_LIBCXXDIR=     ${.CURDIR}/../../contrib/libc++
+HDRDIR=         ${.CURDIR}/../../contrib/libc++/include
+
 INCS=    consumer.h        \
     event.h            \
     event_factory.h        \
@@ -13,6 +16,7 @@ SRCS=    consumer.cc        \
     guid.cc
 INCSDIR= ${INCLUDEDIR}/devdctl
+CFLAGS+= -isystem ${_LIBCXXDIR} -nostdinc++ -nostdlib -I${HDRDIR}
 WARNS?=    3
 PRIVATELIB=    true