fix(main/libevent): override FindThreads configure step

The cmake test to find the pthreads functions looks for
pthread_cancel, which is not implemented on android.  As such, it
fails to find any library with pthread functionality, and the
configure step fails.

This is a cmake issue and not a libevent issue.

packages/libevent/CMakeLists.txt.patch

@@ -0,0 +1,12 @@
+--- ./CMakeLists.txt.orig	2022-08-30 11:05:57.580636738 +0200
++++ ./CMakeLists.txt	2022-08-30 11:06:47.268305387 +0200
+@@ -859,7 +859,8 @@
+     if (WIN32)
+         list(APPEND SRC_CORE evthread_win32.c)
+     else()
+-        find_package(Threads REQUIRED)
++        set(CMAKE_THREAD_LIBS_INIT "")
++        set(CMAKE_USE_PTHREADS_INIT 1) 
+         if (NOT CMAKE_USE_PTHREADS_INIT)
+             message(FATAL_ERROR
+                     "Failed to find Pthreads, set EVENT__DISABLE_THREAD_SUPPORT to disable")

packages/libevent/build.sh

@@ -3,7 +3,7 @@ TERMUX_PKG_DESCRIPTION="Library that provides asynchronous event notification"
 TERMUX_PKG_LICENSE="BSD 3-Clause"
 TERMUX_PKG_MAINTAINER="@termux"
 TERMUX_PKG_VERSION=2.1.12
-TERMUX_PKG_REVISION=1
+TERMUX_PKG_REVISION=2
 TERMUX_PKG_SRCURL=https://github.com/libevent/libevent/archive/release-${TERMUX_PKG_VERSION}-stable.tar.gz
 TERMUX_PKG_SHA256=7180a979aaa7000e1264da484f712d403fcf7679b1e9212c4e3d09f5c93efc24
 TERMUX_PKG_AUTO_UPDATE=true