在CMakeLists.txt文件中，创建一个缓存变量，如下所示：

SET(MY_VARIABLE "option_value" CACHE STRING "Some user-specified option")

来源：https://cmake.org/cmake/help/latest/command/set.html#set-cache-entry
然后，使用GUI（ccmake或cmake-gui）设置该高速缓存变量，或在cmake命令行上使用-D指定变量得值：

cmake -DMY_VARIABLE:STRING=option_value2

如果您的选项实际上是布尔值，请将缓存变量修改为布尔值。

在Ubuntu 16.04上运行CMake 3.13

此方法更灵活，因为它不将MY_VARIABLE约束为类型：

$ cat CMakeLists.txt 
message("MY_VARIABLE=${MY_VARIABLE}")
if( MY_VARIABLE ) 
    message("MY_VARIABLE evaluates to True")
endif()

$ mkdir build && cd build

$ cmake ..
MY_VARIABLE=
-- Configuring done
-- Generating done
-- Build files have been written to: /path/to/build

$ cmake .. -DMY_VARIABLE=True
MY_VARIABLE=True
MY_VARIABLE evaluates to True
-- Configuring done
-- Generating done
-- Build files have been written to: /path/to/build

$ cmake .. -DMY_VARIABLE=False
MY_VARIABLE=False
-- Configuring done
-- Generating done
-- Build files have been written to: /path/to/build

$ cmake .. -DMY_VARIABLE=1
MY_VARIABLE=1
MY_VARIABLE evaluates to True
-- Configuring done
-- Generating done
-- Build files have been written to: /path/to/build

$ cmake .. -DMY_VARIABLE=0
MY_VARIABLE=0
-- Configuring done
-- Generating done
-- Build files have been written to: /path/to/build