[flutter] Fix Windows/Linux build

spine-cpp/spine-cpp/include/spine/MathUtil.h

@@ -33,6 +33,9 @@
 #include <spine/SpineObject.h>
 
 #include <string.h>
+// Needed for older MSVC versions
+#undef min
+#undef max
 
 namespace spine {
 

spine-flutter/setup.sh

@@ -6,4 +6,5 @@ pushd $dir > /dev/null
 # all source files to be under the same folder hierarchy the podspec file resides in.
 cp -r ../spine-cpp/spine-cpp ios/Classes
 cp -r ../spine-cpp/spine-cpp macos/Classes
+cp -r ../spine-cpp/spine-cpp src
 popd

spine-flutter/src/CMakeLists.txt

@@ -3,15 +3,18 @@
 # the plugin to fail to compile for some customers of the plugin.
 cmake_minimum_required(VERSION 3.10)
 
-project(spine_flutter_library VERSION 0.0.1 LANGUAGES C)
+project(spine_flutter_library VERSION 0.0.1)
+
+file(GLOB SPINE_SOURCES "spine-cpp/src/**/*.cpp")
 
 add_library(spine_flutter SHARED
-  "spine_flutter.c"
+  "spine_flutter.cpp"
+  ${SPINE_SOURCES}
 )
 
 set_target_properties(spine_flutter PROPERTIES
   PUBLIC_HEADER spine_flutter.h
   OUTPUT_NAME "spine_flutter"
 )
-
+target_include_directories(spine_flutter PUBLIC spine-cpp/include)
 target_compile_definitions(spine_flutter PUBLIC DART_SHARED_LIB)