Merge pull request #1865 from podsvirov/topic-cmake-project

CMake: Improvements and Bugfixes

cmake/CMakeLists.txt

@@ -86,6 +86,7 @@ if (CMAKE_USE_PTHREADS_INIT)
   add_definitions(-DHAVE_PTHREAD)
 endif (CMAKE_USE_PTHREADS_INIT)
 
+set(_protobuf_FIND_ZLIB)
 if (protobuf_WITH_ZLIB)
   find_package(ZLIB)
   if (ZLIB_FOUND)
@@ -96,6 +97,7 @@ if (protobuf_WITH_ZLIB)
     # Using imported target if exists
     if (TARGET ZLIB::ZLIB)
       set(ZLIB_LIBRARIES ZLIB::ZLIB)
+      set(_protobuf_FIND_ZLIB "if(NOT ZLIB_FOUND)\n  find_package(ZLIB)\nendif()")
     endif (TARGET ZLIB::ZLIB)
   else (ZLIB_FOUND)
     set(HAVE_ZLIB 0)

cmake/libprotobuf.cmake

@@ -56,7 +56,10 @@ set(libprotobuf_files
 
 add_library(libprotobuf ${protobuf_SHARED_OR_STATIC}
   ${libprotobuf_lite_files} ${libprotobuf_files})
-target_link_libraries(libprotobuf ${CMAKE_THREAD_LIBS_INIT} ${ZLIB_LIBRARIES})
+target_link_libraries(libprotobuf ${CMAKE_THREAD_LIBS_INIT})
+if(protobuf_WITH_ZLIB)
+    target_link_libraries(libprotobuf ${ZLIB_LIBRARIES})
+endif()
 target_include_directories(libprotobuf PUBLIC ${protobuf_source_dir}/src)
 if(MSVC AND protobuf_BUILD_SHARED_LIBS)
   target_compile_definitions(libprotobuf

cmake/protobuf-config.cmake.in

 # User options
 include("${CMAKE_CURRENT_LIST_DIR}/protobuf-options.cmake")
 
+# Depend packages
+@_protobuf_FIND_ZLIB@
+
 # Imported targets
 include("${CMAKE_CURRENT_LIST_DIR}/protobuf-targets.cmake")
 

cmake/protobuf-module.cmake.in

@@ -147,7 +147,6 @@ function(_protobuf_find_libraries name filename)
       LOCATION_RELEASE)
     get_target_property(${name}_LIBRARY_DEBUG protobuf::lib${filename}
       LOCATION_DEBUG)
-    endif()
 
     select_library_configurations(${name})
     set(${name}_LIBRARY ${${name}_LIBRARY} PARENT_SCOPE)