From ef618863325a34c7bcbd56930184b5a3d9aed74a Mon Sep 17 00:00:00 2001
From: syzygy1 <3028851+syzygy1@users.noreply.github.com>
Date: Tue, 6 Feb 2018 00:43:29 +0100
Subject: [PATCH] Enable LTO for clang

Enable link-time optimization in the Makefile when compiling with clang.
Also update travis.yml to use clang++-5.0 and llvm-5.0-dev.

No functional change.
---
 .travis.yml  |  7 ++++---
 src/Makefile | 16 +++++-----------
 2 files changed, 9 insertions(+), 14 deletions(-)

diff --git a/.travis.yml b/.travis.yml
index 8586921a..7a0b111f 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -18,11 +18,12 @@ matrix:
       compiler: clang
       addons:
         apt:
-          sources: ['ubuntu-toolchain-r-test']
-          packages: ['clang', 'g++-multilib', 'valgrind', 'expect']
+          sources: ['ubuntu-toolchain-r-test', 'llvm-toolchain-trusty-5.0']
+          packages: ['clang-5.0', 'llvm-5.0-dev', 'g++-multilib', 'valgrind', 'expect']
       env:
-        - COMPILER=clang++
+        - COMPILER=clang++-5.0
         - COMP=clang
+        - LDFLAGS=-fuse-ld=gold
 
     - os: osx
       compiler: gcc
diff --git a/src/Makefile b/src/Makefile
index 72afcc35..f6f36727 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -302,8 +302,6 @@ ifeq ($(optimize),yes)
 
 	ifeq ($(comp),clang)
 		ifeq ($(KERNEL),Darwin)
-				CXXFLAGS += -flto
-				LDFLAGS += $(CXXFLAGS)
 			ifeq ($(arch),i386)
 				CXXFLAGS += -mdynamic-no-pic
 			endif
@@ -349,24 +347,20 @@ endif
 ### 3.8 Link Time Optimization, it works since gcc 4.5 but not on mingw under Windows.
 ### This is a mix of compile and link time options because the lto link phase
 ### needs access to the optimization flags.
-ifeq ($(comp),gcc)
-	ifeq ($(optimize),yes)
-	ifeq ($(debug),no)
+ifeq ($(optimize),yes)
+ifeq ($(debug), no)
+	ifeq ($(comp),$(filter $(comp),gcc clang))
 		CXXFLAGS += -flto
 		LDFLAGS += $(CXXFLAGS)
 	endif
-	endif
-endif
 
-ifeq ($(comp),mingw)
+	ifeq ($(comp),mingw)
 	ifeq ($(KERNEL),Linux)
-	ifeq ($(optimize),yes)
-	ifeq ($(debug),no)
 		CXXFLAGS += -flto
 		LDFLAGS += $(CXXFLAGS)
 	endif
 	endif
-	endif
+endif
 endif
 
 ### 3.9 Android 5 can only run position independent executables. Note that this
-- 
2.39.2