OpenCV errors when including it's headers in C++ - c++

Question

I'm trying to use OpenCV into an existing project; when I add the header #include <opencv2/opencv.hpp> to my source.cc file (just the header, the rest of the code makes no difference), I get the following error.
make all
Building file: source.cc
Invoking: GCC C++ Compiler
g++ -I../__GXX_EXPERIMENTAL_CXX0X__ -I/usr/include/eigen3 -O3 -Wall -c -fmessage-length=0 -std=c++11 -MMD -MP -MF"source.d" -MT"source.d" -o "source.o" "source.cc"
In file included from /usr/local/include/opencv2/core.hpp:3105:0,
from /usr/local/include/opencv2/opencv.hpp:46,
from source.cc:13:
/usr/local/include/opencv2/core/operations.hpp: In member function ‘bool cv::internal::Matx_FastSolveOp<_Tp, m, n>::operator()(const cv::Matx<_Tp, m, m>&, const cv::Matx<_Tp, m, n>&, cv::Matx<_Tp, m, n>&, int) const’:
/usr/local/include/opencv2/core/operations.hpp:131:18: error: missing template arguments before ‘(’ token
return LU(temp.val, m*sizeof(_Tp), m, x.val, n*sizeof(_Tp), n) != 0;
^
make: *** [MapMaker_target_init.o] Error 1
The code looks something like this:
MMaker.cc >>>
#include "MMaker.h"
#include "IMatcher.h"
#include <cvd/image_ref.h>
#include <cvd/vector_image_ref.h>
#include <cvd/vision.h>
#include <cvd/image_interpolate.h>
#include <opencv2/opencv.hpp> // <<<<<<<<<< This is the evil line
bool MMaker::init(AR::IMatcher &matcher)
{
//actually empty
}
MMaker.h >>>
#ifndef __MMAKER_H
#define __MMAKER_H
#include <queue>
namespace AR { class IMatcher; }
class MMaker: protected CVD::Thread
{
public:
bool init(AR::IMatcher &matcher);
// ... more stuff ...
}
//...
IMatcher.h >>>
#ifndef __IMATCHER_H
#define __IMATCHER_H
#include <vector>
#include <string>
namespace cv { class Mat; }
namespace AR
{
class IMatcher
{
// ... IMatcher members declaration ...
}
}
IMatcher.cc >>>
#include "IMatcher.h"
#include <opencv2/opencv.hpp>
#include <opencv2/xfeatures2d.hpp>
// ... IMatcher members implementation ...
I know this is related to how/which files are included or their order perhaps, but haven't got to find what's missing.