From ff05fee2bf1680395142580fed73dd5fed10d11c Mon Sep 17 00:00:00 2001
From: Tim Angus <tim@ngus.net>
Date: Mon, 24 Nov 2025 12:06:29 +0000
Subject: [PATCH] Enable LTO if available

---
 CMakeLists.txt                   | 6 ++++++
 cmake/platforms/emscripten.cmake | 3 +++
 2 files changed, 9 insertions(+)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 5c7336b3..c527b9f3 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -11,6 +11,12 @@ include(identity)
 
 project(${PROJECT_NAME} VERSION ${PROJECT_VERSION} LANGUAGES C)
 
+include(CheckIPOSupported)
+check_ipo_supported(RESULT IPO_SUPPORTED)
+if(IPO_SUPPORTED)
+    set(CMAKE_INTERPROCEDURAL_OPTIMIZATION TRUE)
+endif()
+
 option(BUILD_SERVER "Build dedicated server" ON)
 option(BUILD_CLIENT "Build client" ON)
 option(BUILD_RENDERER_GL1 "Build GL1 renderer" ON)
diff --git a/cmake/platforms/emscripten.cmake b/cmake/platforms/emscripten.cmake
index 30fd9105..6948845c 100644
--- a/cmake/platforms/emscripten.cmake
+++ b/cmake/platforms/emscripten.cmake
@@ -15,6 +15,9 @@ set(USE_OPENAL_DLOPEN OFF CACHE INTERNAL "")
 set(BUILD_GAME_LIBRARIES OFF CACHE INTERNAL "")
 set(USE_HTTP OFF CACHE INTERNAL "")
 
+# Disable LTO since the libraries Emscripten provides aren't LTO enabled
+set(CMAKE_INTERPROCEDURAL_OPTIMIZATION FALSE)
+
 list(APPEND CLIENT_LINK_OPTIONS
     -sTOTAL_MEMORY=256MB
     -sSTACK_SIZE=5MB