diff --git a/plugins/FeedReader/CMakeLists.txt b/plugins/FeedReader/CMakeLists.txt
index 1f1e57675..450a246cb 100644
--- a/plugins/FeedReader/CMakeLists.txt
+++ b/plugins/FeedReader/CMakeLists.txt
@@ -96,6 +96,7 @@ set_target_properties(FeedReader PROPERTIES
 # --- Links ---
 if(WIN32)
     target_link_libraries(FeedReader PRIVATE retroshare retroshare-gui)
+    target_compile_definitions(FeedReader PRIVATE WINDOWS_SYS)
 endif()
 
 target_link_libraries(FeedReader PRIVATE
diff --git a/plugins/VOIP/CMakeLists.txt b/plugins/VOIP/CMakeLists.txt
index d58e7fca7..7e5ec904f 100644
--- a/plugins/VOIP/CMakeLists.txt
+++ b/plugins/VOIP/CMakeLists.txt
@@ -89,6 +89,9 @@ set_target_properties(VOIP PROPERTIES
 )
 
 target_compile_definitions(VOIP PRIVATE __STDC_CONSTANT_MACROS)
+if(WIN32)
+    target_compile_definitions(VOIP PRIVATE WINDOWS_SYS)
+endif()
 
 # --- Links ---
 if(WIN32)