--- ffi/Makefile.freebsd.orig	2020-01-03 17:02:39 UTC
+++ ffi/Makefile.freebsd
@@ -1,7 +1,7 @@
 
-CXX = clang++ -std=c++11 -stdlib=libc++
-CXXFLAGS = $(LLVM_CXXFLAGS)
-LDFLAGS = $(LLVM_LDFLAGS)
+CXX ?= clang++
+CXXFLAGS := $(CPPFLAGS) $(CXXFLAGS) $(LLVM_CXXFLAGS)
+LDFLAGS := $(LDFLAGS) $(LLVM_LDFLAGS)
 LIBS = $(LLVM_LIBS)
 INCLUDE = core.h
 SRC = assembly.cpp bitcode.cpp core.cpp initfini.cpp module.cpp value.cpp \