GLFW in Code::Blocks

The error you’re getting is a link error. It’s likely that the GLFW library you have is the wrong one - where did you get your library from?

Note that an alternative is building from source, this post covers how for Code::Blocks.

Also do note that both MinGW and Code Blocks are not the easiest approach to use for Windows development, you might find using cmake and Visual Studio Community edition (which is free) easier.