create cmake targets for proper lib export

DarknetConfig.cmake.in

@@ -0,0 +1,33 @@
+# Config file for the Darknet package
+# It defines the following variables
+#  Darknet_INCLUDE_DIRS - include directories for Darknet
+#  Darknet_LIBRARIES    - libraries to link against
+
+# Compute paths
+get_filename_component(Darknet_CMAKE_DIR "${CMAKE_CURRENT_LIST_FILE}" PATH)
+set(Darknet_INCLUDE_DIRS "@CONF_INCLUDE_DIRS@")
+
+include(CMakeFindDependencyMacro)
+
+find_dependency(OpenCV REQUIRED)
+
+if(@ENABLE_CUDA@)
+  find_dependency(CUDNN)
+endif()
+
+set(CMAKE_THREAD_PREFER_PTHREAD ON)
+find_dependency(Threads)
+
+if(@MSVC@)
+  find_dependency(PThreads_windows)
+endif()
+
+if("@CMAKE_VERSION@" VERSION_GREATER "3.9.0")
+  find_dependency(OpenMP)
+endif()
+
+# Our library dependencies (contains definitions for IMPORTED targets)
+include("${Darknet_CMAKE_DIR}/DarknetTargets.cmake")
+
+# These are IMPORTED targets created by DarknetTargets.cmake
+set(Darknet_LIBRARIES darklib)