zmq: switch to building with CMake

Faster compilation.

Before:

time make package/zmq/compile -j 12
Executed in   24.98 secs   fish           external
   usr time   97.41 secs  263.00 micros   97.40 secs
   sys time   12.51 secs   34.00 micros   12.51 secs

After:

time make package/zmq/compile -j 12
Executed in   18.17 secs   fish           external
   usr time   85.22 secs  248.00 micros   85.22 secs
   sys time    9.23 secs   32.00 micros    9.23 secs

Signed-off-by: Rosen Penev <rosenp@gmail.com>
(cherry picked from commit da3409bc3d)

libs/zmq/patches/010-cmake.patch

@@ -0,0 +1,20 @@
+--- a/CMakeLists.txt
++++ b/CMakeLists.txt
+@@ -3,6 +3,8 @@
+ cmake_minimum_required(VERSION 2.8.11)
+ project(ZeroMQ)
+ 
++include(FindPkgConfig)
++
+ option(WITH_OPENPGM "Build with support for OpenPGM" OFF)
+ 
+ if(APPLE)
+@@ -21,7 +23,7 @@ if (NOT ENABLE_CURVE)
+     message (STATUS "CURVE security is disabled")
+ 
+ elseif (WITH_LIBSODIUM)
+-    find_package (Sodium)
++    pkg_search_module (SODIUM REQUIRED libsodium)
+     if (SODIUM_FOUND)
+         message (STATUS "Using libsodium for CURVE security")
+         include_directories (${SODIUM_INCLUDE_DIRS})