【MLT编译问题】"PkgConfig:xml" includes non-existent path

使用 cmake .. 编译 mlt 框架时，遇到了如下问题：

CMake Error in src/modules/xml/CMakeLists.txt:
  Imported target "PkgConfig::xml" includes non-existent path

    "/usr/include/libxml2"

  in its INTERFACE_INCLUDE_DIRECTORIES.  Possible reasons include:

  * The path was deleted, renamed, or moved to another location.

  * An install or uninstall procedure did not complete successfully.

  * The installation package was faulty and references files it does not
  provide.

通过查看 mlt 中关于 libxml2 的配置可以发现在 CMakeLists.txt 中通过 pkgconfig 添加的依赖。
具体的原因应该是和 cmake 和 pkgconfig 的语法相关，通过查询资料，得到如下解决方案，亲测可行：

• 通过 brew info libxml2 查看 libxml2 的安装路径

  • 路径为：/usr/local/Cellar/libxml2/2.9.9_2

• 打开该路径下的 lib/pkgconfig/libxml-2.0.pc 文件

  把
  includedir=${prefix}/include
  修改为
  includedir=${pc_sysrootdir}${prefix}/include