vpath && srcdir

If you want to build the project in a different folder of the original code.

1. mkdir build // create a new folder called build

2. ../configure in the build folder

3. it will create a config.status and makefile

4. but when you type  ""make"", it will produce errors

5. then you can change the VPATH and srcdir .
to indicate where the source code is located. In our case , they are located in the code folder

6. then type make, it will create new errors
fatal error: opening dependency file .deps/hello.Tpo: Permission denied

7. sudo make and it proceeds successfully