To build win32 DLL:
  - install Digital Mars C compiler (dmc)
  - make chacha8.def thus:
  
		LIBRARY "libchacha8.dll"
		DESCRIPTION "ChaCha8 stream cipher built by Digital Mars C compiler"
		EXETYPE NT
		SUBSYSTEM WINDOWS
		CODE SHARED EXECUTE
		DATA WRITE
		EXPORTS
			ECRYPT_init
			ECRYPT_keysetup
			ECRYPT_ivsetup
			ECRYPT_encrypt_bytes
			ECRYPT_decrypt_bytes
			ECRYPT_keystream_bytes
			getCtxSize
			isValidKeySize
			isValidIVSize
			getChunkSize
 
  - fm DOS box, compile with:
  
        dmc -WD chacha8.c ecrypt-plus.c
  
  - the above will produce "chacha8.DLL".  For reasons of consistency, 
    rename it to "libchacha8.dll"