The library seems to be 'gdi32':
https://msdn.microsoft.com/en-us/library/vs/alm/dd144925%28v=vs.85%29.aspx
A library can be either static or dynamic. Static library is just a collection of object code and linker effectively copies code into executable during linking. Statically linked executable is a large monolith, but self-sufficient.
Dynamic library is object code too, but rather than copying actual code, the linker adds call code 'stubs' into the executable. When the executable (your program) is run, the library file is linked in and code is executed from it. Thus, the executable file does not work without the library file(s). The executable file is smaller and many programs may use same library; less duplication.
In *nix a dynamic library has extension .so
In OS X a dynamic library has extension .dyld
In Windows a dynamic library has extension .dll, but there is also a .lib file created with the dll that is a small static library containing the stubs thatthe linker inserts into the executable for the executable to link the dll.
The linker of GCC in Windows uses some mixture of library types.