From 923c52ffbb79526ca711fa98b5e865d210d01941 Mon Sep 17 00:00:00 2001
From: Thomas Haller <thaller@redhat.com>
Date: Fri, 10 Feb 2017 12:22:21 +0100
Subject: build: test for support of -flto compiler flag

... and prepend the $ld_gc_flags instead of appending to the $CFLAGS.
---
 m4/compiler_options.m4 | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

(limited to 'm4/compiler_options.m4')

diff --git a/m4/compiler_options.m4 b/m4/compiler_options.m4
index fa35b91681..5275281d71 100644
--- a/m4/compiler_options.m4
+++ b/m4/compiler_options.m4
@@ -128,9 +128,14 @@ fi
 AC_DEFUN([NM_LTO],
 [AC_ARG_ENABLE(lto, AS_HELP_STRING([--enable-lto], [Enable Link Time Optimization for smaller size (default: no)]))
 if (test "${enable_lto}" = "yes"); then
-    CFLAGS="-flto $CFLAGS"
+	CC_CHECK_FLAG_APPEND([lto_flags], [CFLAGS], [-flto])
+	if (test -n "${lto_flags}"); then
+		CFLAGS="-flto $CFLAGS"
+	else
+		AC_MSG_ERROR([Link Time Optimization -flto is not supported.])
+	fi
 else
-    enable_lto='no'
+	enable_lto='no'
 fi
 ])
 
@@ -140,7 +145,7 @@ if (test "${enable_ld_gc}" != "no"); then
 	CC_CHECK_FLAG_APPEND([ld_gc_flags], [CFLAGS], [-fdata-sections -ffunction-sections -Wl,--gc-sections])
 	if (test -n "${ld_gc_flags}"); then
 		enable_ld_gc="yes"
-		CFLAGS="$CFLAGS $ld_gc_flags"
+		CFLAGS="$ld_gc_flags $CFLAGS"
 	else
 		if (test "${enable_ld_gc}" = "yes"); then
 			AC_MSG_ERROR([Unused symbol eviction requested but not supported.])
-- 
cgit v1.2.1