math.h not found when using llvm

I'm trying to build a python wrapper using the following Makefile:

CC=/usr/local/opt/llvm/bin/clang

OS_NAME=$(shell uname -s)
ifeq ($(OS_NAME),Linux) 
  LAPACKLDFLAGS=/usr/lib64/atlas/libsatlas.so   # single-threaded blas
  #LAPACKLDFLAGS=/usr/lib64/atlas/libtatlas.so  # multi-threaded blas
  #BLAS_THREADING=-D MULTITHREADED_BLAS # remove this if wrong
endif
ifeq ($(OS_NAME),Darwin)  # Mac OS X
  LAPACKLDFLAGS=-framework Accelerate # for OS X
endif
LAPACKCFLAGS=-Dinteger=int $(BLAS_THREADING)
STATICLAPACKLDFLAGS=-fPIC -Wall -g -fopenmp -static -static-libstdc++ /home/lear/douze/tmp/jpeg-6b/libjpeg.a /usr/lib64/libpng.a /usr/lib64/libz.a /usr/lib64/libblas.a /usr/lib/gcc/x86_64-redhat-linux/4.9.2/libgfortran.a /usr/lib/gcc/x86_64-redhat-linux/4.9.2/libquadmath.a # statically linked version

CFLAGS= -fPIC -Wall -g -std=c++11 $(LAPACKCFLAGS) -fopenmp -DUSE_OPENMP -O3
LDFLAGS=-fPIC -Wall -g -ljpeg -lpng -fopenmp
CPYTHONFLAGS=-I/usr/include/python2.7 

SOURCES := $(shell find . -name '*.cpp' ! -name 'deepmatching_matlab.cpp')
OBJ := $(SOURCES:%.cpp=%.o)
HEADERS := $(shell find . -name '*.h')


all: deepmatching 

.cpp.o:  %.cpp %.h
    $(CC) -o $@ $(CFLAGS) -c $+

deepmatching: $(HEADERS) $(OBJ)
    $(CC) -o $@ $^ $(LDFLAGS) $(LAPACKLDFLAGS)

deepmatching-static: $(HEADERS) $(OBJ)
    $(CC) -o $@ $^ $(STATICLAPACKLDFLAGS)

python: $(HEADERS) $(OBJ)
#   swig -python $(CPYTHONFLAGS) deepmatching.i # not necessary, only do if you have swig compiler
    /usr/local/opt/llvm/bin/clang $(CFLAGS) -c deepmatching_wrap.c $(CPYTHONFLAGS)
    /usr/local/opt/llvm/bin/clang -shared $(LDFLAGS) $(LAPACKLDFLAGS) deepmatching_wrap.o $(OBJ) -o _deepmatching.so $(LIBFLAGS) 

clean:
    rm -f $(OBJ) deepmatching *~ *.pyc .gdb_history deepmatching_wrap.o _deepmatching.so deepmatching.mex???

Previously, CC was set to g++, however, when I tried to build it like this, I'd get "ERROR: clang: error: unsupported option '-fopenmp". Now I installed "brew install llvm" as this comes with the -fopenmp option. The unsupported error is resolved for now, but now the compiler doesn't seem to find a header file:

(base) MacBook-Pro-van-Brent:deepmatching BrentDeHauwere$ make python /usr/local/opt/llvm/bin/clang -o hog.o -fPIC -Wall -g -std=c++11 -Dinteger=int -fopenmp -DUSE_OPENMP -O3 -I/usr/local/opt/llvm/include -c hog.cpp In file included from hog.cpp:18: In file included from ./std.h:20: /usr/local/opt/llvm/bin/../include/c++/v1/math.h:300:15: fatal error: 'math.h' file not found #include_next <math.h> ^~~~~~~~ 1 error generated. make: *** [hog.o] Error 1

I've tried setting options (I might have set them incorrectly) like -L/usr/local/opt/llvm/lib and -I/usr/local/opt/llvm/include, but no result so far. Any idea how I could point the compiler to the right direction for the header files?