Now after installing all dependencies, which weer required in building nghttp/2. main point came for building it on windows.
the steps were given on the website

Building from git
$ autoreconf -i
$ automake
$ autoconf
$ ./configure
$ make
Notes for building on Windows (MSVC)

1. Install cmake for windows

1. Open "Visual C++ ... Native Build Tool Command Prompt", and inside nghttp2 directly, run cmake.

1. Then run cmake --build to build library.

1. nghttp2.dll, nghttp2.lib, nghttp2.exp are placed under lib directory.

Building from git is easy, but please be sure that at least autoconf 2.68 is used:

To compile the source code, gcc >= 4.8.3 or clang >= 3.4 is required.

Note

To enable mruby support in nghttpx, run git submodule update --init before running configure script, and use --with-mruby configure option.

Note

Mac OS X users may need the --disable-threads configure option to disable multi-threading in nghttpd, nghttpx and h2load to prevent them from crashing. A patch is welcome to make multi threading work on Mac OS X platform.

Note

To compile the associated applications (nghttp, nghttpd, nghttpx and h2load), you must use the --enable-app configure option and ensure that the specified requirements above are met. Normally, configure script checks required dependencies to build these applications, and enable --enable-app automatically, so you don't have to use it explicitly. But if you found that applications were not built, then using --enable-app may find that cause, such as the missing dependency.

The easiest way to build native Windows nghttp2 dll is use cmake. The free version of Visual C++ Build Tools works fine.

Note that the above steps most likely produce nghttp2 library only. No bundled applications are compiled.