The Android SDK includes the Android NDK, which in turn contains a customised GCC based tool chain for Android on ARM processors; The question is how to build the NDK tool chain to run on Windows to target x86 Android?
The tool chain is already setup to build on Windows (cygwin) targeting ARM; There are also existing pre-built (unofficial) NDKs for targeting x86, but these contain pre-built tools for x86 Linux, not Windows.
The NDK contains a build-toolchain.sh script to rebuild its tool chain; the question is, what specifically needs done to get that to build a tool chain targeting Android x86?