https://gitlab.com/Remmina/Remmina/-/merge_requests/2611

--- Remmina-1.4.36/src/CMakeLists.txt.orig
+++ Remmina-1.4.36/src/CMakeLists.txt
@@ -200,7 +200,7 @@
 endif()
 
 if(OPENSSL_FOUND)
-  include_directories(${OPENSSL_INCLUDE_DIRS})
+  include_directories(${OPENSSL_INCLUDE_DIR})
   target_link_libraries(remmina ${OPENSSL_LIBRARIES})
 endif()