我只需要更改搜索路径，告诉Xcode opencv的位置即可。 以下是我的搜索路径：
Framework search path: /usr/local/lib
Library search path: /usr/local/Cellar/opencv/2.4.11/lib
/usr/local/Cellar/opencv/2.4.11_1/lib
/user/local/lib
Header search path: /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include
/usr/local/include
错误信息：
In file included from /Users/lilisun/Documents/opencv_projects/faceExtractor/faceExtractor/main.cpp:8:
In file included from /usr/local/include/opencv2/objdetect/objdetect.hpp:46:
In file included from /usr/local/include/opencv2/core/core.hpp:49:
In file included from /usr/local/include/opencv2/core/types_c.h:55:
In file included from /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.10.sdk/usr/include/assert.h:44:
In file included from /usr/local/include/c++/5.1.0/tr1/stdlib.h:32:
In file included from /usr/local/include/c++/5.1.0/tr1/cstdlib:34:
/usr/local/include/c++/5.1.0/cstdlib:118:11: error: no member named 'div_t' in the global namespace
using ::div_t;
~~^
/usr/local/include/c++/5.1.0/cstdlib:119:11: error: no member named 'ldiv_t' in the global namespace
using ::ldiv_t;
~~^
/usr/local/include/c++/5.1.0/cstdlib:121:11: error: no member named 'abort' in the global namespace
using ::abort;
~~^
/usr/local/include/c++/5.1.0/cstdlib:122:11: error: no member named 'abs' in the global namespace
using ::abs;
~~^
/usr/local/include/c++/5.1.0/cstdlib:123:11: error: no member named 'atexit' in the global namespace
using ::atexit;
~~^
/usr/local/include/c++/5.1.0/cstdlib:129:11: error: no member named 'atof' in the global namespace
using ::atof;
~~^
/usr/local/include/c++/5.1.0/cstdlib:130:11: error: no member named 'atoi' in the global namespace
using ::atoi;
~~^
/usr/local/include/c++/5.1.0/cstdlib:131:11: error: no member named 'atol' in the global namespace
using ::atol;
~~^
/usr/local/include/c++/5.1.0/cstdlib:132:11: error: no member named 'bsearch' in the global namespace
using ::bsearch;
~~^
/usr/local/include/c++/5.1.0/cstdlib:133:11: error: no member named 'calloc' in the global namespace
using ::calloc;
~~^
/usr/local/include/c++/5.1.0/cstdlib:134:11: error: no member named 'div' in the global namespace
using ::div;
~~^
/usr/local/include/c++/5.1.0/cstdlib:135:11: error: no member named 'exit' in the global namespace
using ::exit;
~~^
/usr/local/include/c++/5.1.0/cstdlib:136:11: error: no member named 'free' in the global namespace
using ::free;
~~^
/usr/local/include/c++/5.1.0/cstdlib:137:11: error: no member named 'getenv' in the global namespace
using ::getenv;
~~^
/usr/local/include/c++/5.1.0/cstdlib:138:11: error: no member named 'labs' in the global namespace
using ::labs;
~~^
/usr/local/include/c++/5.1.0/cstdlib:139:11: error: no member named 'ldiv' in the global namespace
using ::ldiv;
~~^
/usr/local/include/c++/5.1.0/cstdlib:140:11: error: no member named 'malloc' in the global namespace
using ::malloc;
~~^
/usr/local/include/c++/5.1.0/cstdlib:142:11: error: no member named 'mblen' in the global namespace
using ::mblen;
~~^
/usr/local/include/c++/5.1.0/cstdlib:143:11: error: no member named 'mbstowcs' in the global namespace
using ::mbstowcs;
~~^
fatal error: too many errors emitted, stopping now [-ferror-limit=]
20 errors generated.