[Boost-users] Passing -D options with b2 to ASIO when compiling with mingw64 ucrt64?

Hi, I try to compile Boost with MingW64 with ucrt64. I get warnings saying I should define _WIN32_WINNT with 0x0601 or higher and an error saying I must define USE_W32_SOCKETS. Is it possible to pass these on a command line to b2 or otherwise, without interfering with Boost's source? TIA -- Groeten, Joost