- Building libliquid.dll and libliquid.a:
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- Install the Msys2 distribution as described on their site (https://msys2.github.io/) 
- Add mingw32 and mingw64 compiler to the Msys2 installation.
- Copy config.h, makefile.mingw32, makefile.mingw64 in the liquid-dsp root directory.
- Run a Msys2 Win32 shell (mingw32.exe) and execute 'make -f makefile.mingw32 -j clean' then 'make -f makefile.mingw32 -j' to compile a libliquid.dll 32bit Windows Dll.
- Run a Msys2 Win64 shell (mingw64.exe) and execute 'make -f makefile.mingw64 -j clean' then 'make -f makefile.mingw64 -j' to compile a libliquid.dll 64bit Windows Dll.

This process generates a .dll, .a together with libliquid.def the listing exported functions, and libliquid.lib the import lib matching the dll.

In order to develop with Visual Studio, you need both the include/liquid.h at source level, and the libliquid.lib import library referenced in your project.