This is a clean copy of libevent-2.0.21-stable with the following modifications:

1. Add the following files:

linux/event2/event-config.h
mac/event2/event-config.h
android/event2/event-config.h

These files are taken from libevent-2.0.21-stable built on the development environment indicated by the first path component. You have to run "./configure" and "make" to get all of the pre-processing done. The file can then be found in "include/event2/".

2. This is ugly, prepare yourself. OS X has a weird problem with how the "TAILQ_END(head)" is used, causing a linking error. Just replace all use of the "TAILQ_END(head)" macro with "NULL".

3. Apply "add mac-arc4random-buf.patch", which removes some bad OS X compatibility code. This will allow libevent to compile on all supported versions of OS X.

4. Apply "openbsd-no-arc4random_addrandom.patch", which fixes the build on OpenBSD (which doesnt provide arc4random_addrandom anymore, see #931354)

5. Apply "libevent-use-non-deprecated-syscalls.patch", which fixes the build on AArch64 architecture (which does not provide deprecated syscalls)

6. Apply "libevent-dont-use-issetugid-on-android.patch'. which fixes the build on Android L preview
