Wrap find_package

CMakeLists.txt

@@ -6,22 +6,24 @@ include (DetectCPPZMQVersion)
 
 project(cppzmq VERSION ${DETECTED_CPPZMQ_VERSION})
 
-find_package(ZeroMQ QUIET)
+if (NOT TARGET libzmq)
+  find_package(ZeroMQ QUIET)
 
-# libzmq autotools install: fallback to pkg-config
-if(NOT ZeroMQ_FOUND)
+  # libzmq autotools install: fallback to pkg-config
+  if(NOT ZeroMQ_FOUND)
     message(STATUS "CMake libzmq package not found, trying again with pkg-config (normal install of zeromq)")
     list (APPEND CMAKE_MODULE_PATH ${CMAKE_CURRENT_LIST_DIR}/libzmq-pkg-config)
     find_package(ZeroMQ REQUIRED)
-endif()
+  endif()
 
-# TODO "REQUIRED" above should already cause a fatal failure if not found, but this doesn't seem to work
-if(NOT ZeroMQ_FOUND)
+  # TODO "REQUIRED" above should already cause a fatal failure if not found, but this doesn't seem to work
+  if(NOT ZeroMQ_FOUND)
     message(FATAL_ERROR "ZeroMQ was not found, neither as a CMake package nor via pkg-config")
-endif()
+  endif()
 
-if (ZeroMQ_FOUND AND (NOT TARGET libzmq OR NOT TARGET libzmq-static))
-  message(FATAL_ERROR "ZeroMQ version not supported!")
+  if (ZeroMQ_FOUND AND (NOT TARGET libzmq OR NOT TARGET libzmq-static))
+    message(FATAL_ERROR "ZeroMQ version not supported!")
+  endif()
 endif()
 
 if (EXISTS "${CMAKE_SOURCE_DIR}/.git")