simplepost.c: fixed compiling with VS before 2015
simplepost.c: fixed compiling with VS before 2015

maru/libmicrohttpd-http2,ghaderer/libmicrohttpd,maru/libmicrohttpd-http2,ghaderer/libmicrohttpd,ghaderer/libmicrohttpd,maru/libmicrohttpd-http2