src: fixes for win32

Update following macros:

* NODE_NET_SOCKET_{READ,WRITE}() - they both take 4 arguments,
  not 2

* NODE_COUNT_GC_PERCENTTIME() - it takes a single argument.

Use INT_PTR instead of INT32 in pointer casts in win32_etw provider.

PR-URL: https://github.com/joyent/node/pull/8294
Reviewed-By: Fedor Indutny <fedor@indutny.com>
build: determine and use EXEEXT on windows

PR-URL: https://github.com/joyent/node/pull/8294
Reviewed-By: Fedor Indutny <fedor@indutny.com>