libevent2: Update to 2.1.11

Update libevent to 2.1.11
Use CMake instead GNU Autotools
Backport following commits:
f05ba67193
..and partially
7201062f3e
to fix compilation

Signed-off-by: Daniel Engberg <daniel.engberg.lists@pyret.net>

package/libs/libevent2/patches/0002-Add-Uninstall.cmake.in-into-dist-archive.patch

@@ -0,0 +1,25 @@
+From f05ba671931e2b4e38459899f6f63f79f99869fe Mon Sep 17 00:00:00 2001
+From: Azat Khuzhin <a3at.mail@gmail.com>
+Date: Sat, 3 Aug 2019 14:32:21 +0300
+Subject: [PATCH] Add Uninstall.cmake.in into dist archive
+
+Fixes: #863
+---
+ Makefile.am | 1 +
+ 1 file changed, 1 insertion(+)
+
+diff --git a/Makefile.am b/Makefile.am
+index af75a963..92f9433c 100644
+--- a/Makefile.am
++++ b/Makefile.am
+@@ -127,6 +127,7 @@ CMAKE_FILES = \
+ 	cmake/LibeventConfig.cmake.in \
+ 	cmake/LibeventConfigVersion.cmake.in \
+ 	cmake/VersionViaGit.cmake \
++	cmake/Uninstall.cmake.in \
+ 	event-config.h.cmake \
+ 	evconfig-private.h.cmake \
+ 	CMakeLists.txt
+-- 
+2.22.0
+