这真让我发疯。在我的CMakeLists.txt中，我有：

find_package(Boost 1.63.0 REQUIRED SYSTEM)

结果：

[0/1] Re-running CMake...
Build type: Release
CMake Error at /usr/share/cmake-3.10/Modules/FindBoost.cmake:1947 (message):
  Unable to find the requested Boost libraries.

  Boost version: 1.65.1

  Boost include path: /usr/include

  Could not find the following Boost libraries:

          boost_system

但是：

$ locate libboost_system
/usr/lib/x86_64-linux-gnu/libboost_system.a
/usr/lib/x86_64-linux-gnu/libboost_system.so
/usr/lib/x86_64-linux-gnu/libboost_system.so.1.65.1

并且：

$ sudo apt install libboost-all-dev
Reading package lists... Done
Building dependency tree       
Reading state information... Done
libboost-all-dev is already the newest version (1.65.1.0ubuntu1).

我以前使用过自动编译的1.63.0，但是已经删除了/usr/local/lib和/usr/local/include中的所有文件。也许还是在这里出没。

如果我发现这样的Boost（没有系统）：

find_package(Boost 1.63.0 REQUIRED)

..然后配置成功，但不会链接到${Boost_SYSTEM_libraRY}：

/usr/bin/ld: src/app/CMakeFiles/app.dir/application.cpp.o: undefined reference to symbol '_ZN5boost6system15system_categoryEv'
//usr/lib/x86_64-linux-gnu/libboost_system.so.1.65.1: error adding symbols: DSO missing from command line
collect2: error: ld returned 1 exit status