From ec232a936537a0a3eda5f164c038c503a7af506e Mon Sep 17 00:00:00 2001
From: Nadia Holmquist Pedersen <nadia@nhp.sh>
Date: Fri, 6 Nov 2020 12:03:02 +0100
Subject: [PATCH] Fix building the Qt frontend with LTO (#802)

* Remove unnecessary -fno-pic/-no-pie, fixes LTO builds

* restore -no-pie because GNOME is derpy
---
 CMakeLists.txt | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 8b8d699b..08f7f8d3 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -65,9 +65,21 @@ if (CMAKE_BUILD_TYPE STREQUAL Release)
 	add_link_options(-s)
 endif()
 
-add_compile_options(-fno-pic)
 add_link_options(-no-pie)
 
+if (ENABLE_LTO)
+	add_compile_options(-flto)
+	add_link_options(-flto)
+
+	if (CMAKE_C_COMPILER_ID STREQUAL "GCC")
+		set(CMAKE_AR "gcc-ar")
+		set(CMAKE_C_ARCHIVE_CREATE "<CMAKE_AR> qcs <TARGET> <LINK_FLAGS> <OBJECTS>")
+		set(CMAKE_C_ARCHIVE_FINISH   true)
+		set(CMAKE_CXX_ARCHIVE_CREATE "<CMAKE_AR> qcs <TARGET> <LINK_FLAGS> <OBJECTS>")
+		set(CMAKE_CXX_ARCHIVE_FINISH   true)
+	endif()
+endif()
+
 option(BUILD_QT_SDL "Build Qt/SDL frontend" ON)
 
 if (WIN32)