MacOS – OpenCV library not installing after using cmake

I use Yosemite 10.10, and I need to build and install the OpenCV library using cmake-gui. I was able to configure and generate the binaries readily. But when I try to 'make' the library using the terminal
sudo make -j4
in the binaries folder, I get the following error –

Building CXX object modules/core/CMakeFiles/opencv_core.dir/src/parallel.cpp.o
In file included from /usr/include/os/object.h:27:0,
             from /usr/include/dispatch/dispatch.h:48,
             from /Users/imecindia/Desktop/Downloaded Libraries/opencv-3.0.0-beta/modules/core/src/parallel.cpp:106:
/usr/include/os/base.h:113:20: error: missing binary operator before token "("
#if __has_extension(attribute_overloadable)
                ^
/usr/include/os/base.h:119:54: error: missing binary operator before token "("
#if __has_feature(objc_fixed_enum) || __has_extension(cxx_strong_enums)
                                                  ^
[ 45%] Building CXX object modules/core/CMakeFiles/opencv_core.dir/src/pca.cpp.o
In file included from /usr/include/dispatch/dispatch.h:51:0,
             from /Users/imecindia/Desktop/Downloaded Libraries/opencv-3.0.0-beta/modules/core/src/parallel.cpp:106:
/usr/include/dispatch/object.h:325:20: error: missing binary operator before token "("
#if __has_extension(c_generic_selections)
                ^
/usr/include/dispatch/object.h:363:20: error: missing binary operator before token "("
#if __has_extension(c_generic_selections)
                ^
/usr/include/dispatch/object.h:391:20: error: missing binary operator before token "("
#if __has_extension(c_generic_selections)
                ^
/usr/include/dispatch/object.h:423:20: error: missing binary operator before token "("
#if __has_extension(c_generic_selections)
                ^
/usr/include/dispatch/object.h:143:15: error: expected unqualified-id before '^' token
typedef void (^dispatch_block_t)(void);
           ^
/usr/include/dispatch/object.h:143:15: error: expected ')' before '^' token
/usr/include/dispatch/object.h:362:3: error: 'dispatch_block_t' has not been declared
dispatch_block_t notification_block);
^
make[2]: *** [modules/core/CMakeFiles/opencv_core.dir/src/parallel.cpp.o] Error 1
make[2]: *** Waiting for unfinished jobs....
make[1]: *** [modules/core/CMakeFiles/opencv_core.dir/all] Error 2
make: *** [all] Error 2

I get that in multiple places in this particular file,

Also I specified the compiler for using gcc/g++/gfortran that came with MacPorts. It's mandatory that I use the MacPorts compiler btw.

Can someone let me know what I can do?