From 5da1f631bc753655ac94b08a6233eecd0d451327 Mon Sep 17 00:00:00 2001
From: "Arnout Vandecappelle (Essensium/Mind)" <arnout@mind.be>
Date: Fri, 26 Aug 2016 21:55:06 +0200
Subject: [PATCH] Fix LTO support for cross-compilation.

When cross-compiling, the ar and ranlib to be used for LTO are prefixed
by the cross-tuple. gcc-ar and gcc-ranlib may not exist. Cfr.
http://autobuild.buildroot.net/results/f3c/f3c48da3a9706cd366c0e0a96c3cd0ff959f2a78/

Therefore, search for an appropriate lto-ar and lto-ranlib before
enabling LTO.

Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>
---
Submitted upstream: https://github.com/tomba/kmsxx/pull/14
---
 CMakeLists.txt | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index e5b5ea5..c61c81d 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -39,9 +39,15 @@ if (NOT ${U_CMAKE_BUILD_TYPE} MATCHES DEBUG)
     CHECK_CXX_COMPILER_FLAG("-flto" HAS_LTO_FLAG)
 
     if (HAS_LTO_FLAG)
-        set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -flto")
-        set(CMAKE_AR gcc-ar)
-        set(CMAKE_RANLIB gcc-ranlib)
+        find_program(LTO_AR NAMES "${CMAKE_C_COMPILER}-ar" gcc-ar)
+        find_program(LTO_RANLIB NAMES "${CMAKE_C_COMPILER}-ranlib" gcc-ranlib)
+        if (LTO_AR AND LTO_RANLIB)
+            set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -flto")
+            set(CMAKE_AR "${LTO_AR}")
+            set(CMAKE_RANLIB "${LTO_RANLIB}")
+        else()
+            message(STATUS "gcc-ar or gcc-ranlib not found, disabling LTO")
+        endif()
     endif()
 endif()
 
-- 
2.9.3