Add support for build with MinGW

[cwassmuth]

With this commits you can build anyrpc with MinGW 8.1 and Windows 10.

I have not tried if this breaks any other build configuration.

[m-kuhn]

Thanks !

I also had to add this for https://stackoverflow.com/questions/18551409/localtime-r-support-on-mingw

--- a/CMakeLists.txt	2020-01-13 18:31:55.000000000 +0100
+++ b/CMakeLists.txt	2022-07-19 19:29:54.339127866 +0200
@@ -63,6 +63,7 @@
     set( CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /EHsc" )
 elseif (MINGW)
     SET( CMAKE_CXX_FLAGS  "${CMAKE_CXX_FLAGS} -U__STRICT_ANSI__" )
+    add_definitions( -D _POSIX_THREAD_SAFE_FUNCTIONS )
 elseif (BUILD_WITH_ADDRESS_SANITIZE)
     SET( CMAKE_CXX_FLAGS  "${CMAKE_CXX_FLAGS} -fsanitize=address -fno-omit-frame-pointer" )
     SET( ASAN_LIBRARY asan )

[m-kuhn]

It compiles on linux, macos, windows microsoft/vcpkg#25901

[m-kuhn]

Ping @sgieseking does this look good to you?

[sgieseking]

I will see about checking it over the weekend. I don't have MinGW installed on my development computer now.

[FrankXie05]

@sgieseking Is there any progress on this PR? :)

[FrankXie05]

@sgieseking Is there any progress on this PR? :)

[cwassmuth]

I removed the mingw headers. There are not used anymore

[s-weigand]

@sgieseking Are there plans on merging this? 😄