how to create dylibs that link to boost - c++

Question

I am using clang and boost 1.57 on OSX Yosemite. I am trying to create a dylib for a python application (used swig to make the wrappers). I have successfully compiled this code for Windows and Linux, so I know it is the build/link phase on OSX that is causing me issues. Here is my makefile (which is wrong, somehow):
CC=clang++
vpath %.c ./
vpath %.h ./
SRCS=RecorderLib.cpp RecorderLib_wrap.cpp
OBJS=$(SRCS:.cpp=.o)
LIBS= -lpython2.7 -lboost_iostreams-mt -lboost_system-mt -lboost_thread-mt -lboost_date_time-mt -lboost_chrono-mt -lboost\
_filesystem-mt -lboost_regex-mt -lboost_atomic-mt -lboost_serialization-mt -lboost_program_options-mt
CFLAGS=-arch x86_64 -Xarch_x86_64 -mmacosx-version-min=10.5 -pipe -O2 -c -stdlib=libstdc++
LINKFLAGS = -dynamiclib -undefined suppress -flat_namespace
.PHONY: RecorderLib64.dylib
all: RecorderLib_wrap.o RecorderLib.o RecorderLib64.dylib
RecorderLib_wrap.o:
$(CC) RecorderLib_wrap.cpp $(CFLAGS) $(LIBS) -o RecorderLib_wrap.o
RecorderLib.o:
$(CC) RecorderLib.cpp $(CFLAGS) $(LIBS) -o RecorderLib.o
RecorderLib64.dylib:
$(CC) $(LINKFLAGS) $(OBJS) $(LIBS) \
-o RecorderLib64.dylib
mv RecorderLib64.dylib ../../
clean:
rm *.o
If I remove the -undefined suppress -flat_namespace flags, the thing will toss me a million symbol not found for architecture x86_64 errors for all the boost functions that I reference.
When I include those flags, the library compiles but when I fire up the host application I get an error such as
OSError: dlopen(/Users/myself/RecorderApp/src/RecorderLib64.dylib, 6): Symbol not found: __ZN5boost9iostreams15file_descriptor4seekElSt12_Ios_Seekdir
which I interpret to mean the dylib doesn't know about boost.
One other thing that I don't understand, but is possibly related, is that when I compile the source objects, it tosses me errors such as:
clang: warning: -lpython2.7: 'linker' input unused
On linux, you want to link to libraries both at the compile stage and the link stage (at least this is my understanding -- in any case my Makefile.gnu which I am basing this off of does this and works beautifully).
I should also mention that I can compile applications on this system that link to boost and various dylibs and they work perfectly, so I know my boost installation etc. is alright. Also, inspecting the libraries I link to with the file command tells me they are of the correct x86_64 architecture.
Later:
So, I realize now that the symbol(s) not found for architecture x86_64 errors were actually pointing to functions in the stdlib (but were referenced from boost), i.e.:
"std::basic_streambuf<char, std::char_traits<char> >::setbuf(char*, long)", referenced from:
vtable for boost::iostreams::stream_buffer<boost::iostreams::file_descriptor_sink, std::char_traits<char>, std::allocator<char>, boost::iostreams::output> in RecorderLib.o
Changing the makefile so that the min osx version is 10.7 and using -stdlib=libc++ gets rid of all theses errors, but I am still getting symbol(s) not found for a boost:iostreams call:
"boost::iostreams::file_descriptor::seek(long,std::__1::ios_base::seekdir)"