Merge pull request #12 from black-ai/hunter-3.7.1

Update protobuf to 3.7.1

CMakeLists.txt

@@ -0,0 +1,14 @@
+cmake_minimum_required(VERSION 3.0)
+
+include("cmake/HunterGate.cmake")
+HunterGate(
+    URL "https://github.com/ruslo/hunter/archive/v0.23.101.tar.gz"
+    SHA1 "ccb234f5ea9dc89989b28164cb38cb4ebb04237c"
+)
+
+# Project
+project(protobuf C CXX)
+
+hunter_add_package(ZLIB)
+
+add_subdirectory(cmake)

cmake/CMakeLists.txt

@@ -115,10 +115,10 @@ if (protobuf_WITH_ZLIB)
     # Set ZLIB_INCLUDE_DIRECTORIES for compatible
     set(ZLIB_INCLUDE_DIRECTORIES ${ZLIB_INCLUDE_DIRECTORIES} ${ZLIB_INCLUDE_DIRS})
     # Using imported target if exists
-    if (TARGET ZLIB::ZLIB)
-      set(ZLIB_LIBRARIES ZLIB::ZLIB)
+    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)
+    endif (TARGET ZLIB::zlib)
   else (ZLIB_FOUND)
     set(HAVE_ZLIB 0)
     # Explicitly set these to empty (override NOT_FOUND) so cmake doesn't