Add libevent2 component

component/libevent/buildout.cfg

 [buildout]
 parts = libevent
+extends =
+  ../openssl/buildout.cfg
 
 [libevent]
 recipe = slapos.recipe.cmmi
@@ -7,3 +9,11 @@ url = http://www.monkey.org/~provos/libevent-1.4.13-stable.tar.gz
 md5sum = 0b3ea18c634072d12b3c1ee734263664
 configure-options =
   --disable-static
+
+[libevent2]
+<= libevent
+url = https://github.com/libevent/libevent/releases/download/release-2.1.10-stable/libevent-2.1.10-stable.tar.gz
+md5sum = 999caf86f52943af2363bc8077f00167
+environment =
+  CPPFLAGS=-I${openssl:location}/include
+  LDFLAGS=-L${openssl:location}/lib
\ No newline at end of file