Windows下的Qt配置pkg-config环境的解决方案！

【前言】
    我们都知道在Linux系统下配置完opencv环境后，Qt直接按照以下方式就可以直接调用了！这里我们采用的编译器是mingw32-make！

CONFIG
+=
link_pkgconfig
PKGCONFIG
+=
opencv 

    但在windows下面，要么在VS下配置include和lib目录，针对Qt Creator下的多数采用下面的方案：

INCLUDEPATH

+=
D:\opencv\build\include

LIBS

+=
D:\opencv-build\bin\libopencv_core320.dll
LIBS

+=
D:\opencv-build\bin\libopencv_highgui320.dll
LIBS

+=
D:\opencv-build\bin\libopencv_imgcodecs320.dll
LIBS

+=
D:\opencv-build\bin\libopencv_imgproc320.dll
LIBS

+=
D:\opencv-build\bin\libopencv_features2d320.dll
LIBS

+=
D:\opencv-build\bin\libopencv_calib3d320.dll

    如果只使用opencv或许没啥问题，但是往往我们还需要其它第三方的c++库，这时采用这样的方式，工程管理上比较混乱！随无伤大雅，但总觉得别扭！

针对这样的情况，我们往往采用两种方案，分别为Cmake和pkg-config这两种！CMake的确很优秀，但不自动管理Qt自己的内部库，相当于Qt库和第三方库一视同仁，都需要自己配置，这就尴尬了！一般比较复杂且需要跨平台部署的工程才建议使用cmake，平时也没必要自己折腾自己了！

于是下面讨论是pkg-config的方案！
参考网站：https://stackoverflow.com/questions/26453293/what-is-the-best-way-to-install-pkg-config-on-mingw-in-2014

On http://sourceforge.net/p/mingw/mailman/message/31908633/ there
are some instructions from earlier this year:

The FAQ pkg-config information did not work for me: these did:https://github.com/texane/stlink/issues/169
Download these three glib, pkg-config, pkg-config-dev archives and extract contents to C:\MinGW
http://win32builder.gnome.org/packages/3.6/glib_2.34.3-1_win32.zip
http://win32builder.gnome.org/packages/3.6/pkg-config_0.28-1_win32.zip
http://win32builder.gnome.org/packages/3.6/pkg-config-dev_0.28-1_win32.zip

I keep this unaccepted in case someone has a better answer.

最新的pkg-config是0.29的版本，这里是0.28的！pkg-config这个工具比较稳定了，更新频次比较少！0.28与0.29的区别不大，使用是没有问题的！

下载上面的三个工具，分别为glib,pkg-config,pkg-config-dev。将其放置到mingw的安装目录中！这里我使用的是Qt自带的mingw，你可以完全像我这样设置！



将其分别解压，目录结构分别为







将他们目录下文件夹分别拷贝到mingw的安装目录！



在lib目录下创建一个pkgconfig，用于放置opencv.pc文档！



我们最好再设置一下PKG_CONFIG_PATH



现在我们需要找到opencv.pc，将其复制过来并编辑配置一下！



将其拷贝到刚才的PKG_CONFIG_PATH所对应的目录下！
需要注意的是这个opencv.pc文档在widnows下需要修改一下，否则不好使用！
原本的opencv.pc的内容如下

# Package Information for pkg-config

prefix=D:/OpenCV/build/install
exec_prefix=${prefix}
libdir=${exec_prefix}/x86/mingw/lib
includedir_old=${prefix}/include/opencv
includedir_new=${prefix}/include

Name: OpenCV
Description: Open Source Computer Vision Library
Version: 3.3.1
Libs: -L${exec_prefix}/x86/mingw/lib -llibopencv_dnn331d.dll -llibopencv_ml331d.dll -llibopencv_objdetect331d.dll -llibopencv_shape331d.dll -llibopencv_stitching331d.dll -llibopencv_superres331d.dll -llibopencv_videostab331d.dll
-llibopencv_calib3d331d.dll -llibopencv_features2d331d.dll -llibopencv_highgui331d.dll -llibopencv_videoio331d.dll -llibopencv_imgcodecs331d.dll -llibopencv_video331d.dll -llibopencv_photo331d.dll -llibopencv_imgproc331d.dll -llibopencv_flann331d.dll -llibopencv_core331d.dll
Libs.private: -lopengl32 -lglu32
Cflags: -I${includedir_old} -I${includedir_new}

这里我们可以看到上面有prefix，exec_prefix这样的变量，在windows下的pkg-config是无视他们的，都是默认到mingw的安装目录，因此我们需要改为绝对路径！这里设定你自己的目录就可以了！

# Package Information for pkg-config

libdir=D:/OpenCV/build/install/x86/mingw/lib
includedir_old=D:/OpenCV/build/install/include/opencv
includedir_new=D:/OpenCV/build/install/include

Name: OpenCV
Description: Open Source Computer Vision Library
Version: 3.3.1
Libs: -LD:/OpenCV/build/install/x86/mingw/lib -llibopencv_dnn331d.dll -llibopencv_ml331d.dll -llibopencv_objdetect331d.dll -llibopencv_shape331d.dll -llibopencv_stitching331d.dll -llibopencv_superres331d.dll
-llibopencv_videostab331d.dll -llibopencv_calib3d331d.dll -llibopencv_features2d331d.dll -llibopencv_highgui331d.dll -llibopencv_videoio331d.dll -llibopencv_imgcodecs331d.dll -llibopencv_video331d.dll -llibopencv_photo331d.dll -llibopencv_imgproc331d.dll -llibopencv_flann331d.dll
-llibopencv_core331d.dll
Libs.private: -lopengl32 -lglu32
Cflags: -I${includedir_old} -I${includedir_new}

好了，pkg-config环境配置都完成了！

pro工程目录下添加

CONFIG
+=
link_pkgconfig
PKGCONFIG
+=
opencv 

就可以构建使用了！

这样我们就可以拥抱qmake了，无需需要cmake就可以开开心心的添加第三方库了！