[BUG] deferred_with_accumulator example using *nix sleep function, incompatible with Windows

[deanmsands3]

Prerequisites

• [X ] Put an X between the brackets on this line if you have checked that your issue isn't already filed: https://github.com/search?l=&q=repo%3Aetr%2Flibhttpserver&type=Issues

Description

Example deferred_with_accumulator using *nix sleep function, incompatible with Windows

Steps to Reproduce

1. (Fix the ws2_32 linker error for MinGW)
2. Compile examples
3. Compilation fails on deferred_with_accumulator example

Expected behavior:
Proper compilation of all examples

Actual behavior:
Compilation fails with deferred_with_accumulator example

Reproduces how often:
%100 on any system lacking the C sleep() function

Versions

• Windows 10x64
• libhttpserver version: git commit 3ffda7b (compiled)
• libmicrohttpd version (please specify whether compiled or packaged)

If you have problems during build:

• Compiler version: MSYS2/MinGW64 GCC 9.2.0
• autotools version: automake 1.16.1, autoconf 2.69