From b8b65b7be795a5efd9db3a974d02f777b6799806 Mon Sep 17 00:00:00 2001
From: Bruce Dubbs <bdubbs@linuxfromscratch.org>
Date: Sat, 7 Jul 2018 17:48:11 +0000
Subject: Add a configuration option to libffi to ensure proper architecture
 selection.  Include an explanation and how to select alternative options.

git-svn-id: http://svn.linuxfromscratch.org/LFS/trunk/BOOK@11435 4aa44e1e-78dd-0310-a6d2-fbcd4c07a689
---
 chapter06/libffi.xml | 21 ++++++++++++++++++++-
 1 file changed, 20 insertions(+), 1 deletion(-)

(limited to 'chapter06/libffi.xml')

diff --git a/chapter06/libffi.xml b/chapter06/libffi.xml
index 5ebc27270..c0aba3cd5 100644
--- a/chapter06/libffi.xml
+++ b/chapter06/libffi.xml
@@ -55,7 +55,26 @@ sed -e '/^includedir/ s/=.*$/=@includedir@/' \
 
     <para>Prepare libffi for compilation:</para>
 
-<screen><userinput remap="configure">./configure --prefix=/usr --disable-static</userinput></screen>
+<screen><userinput remap="configure">./configure --prefix=/usr --disable-static --with-gcc-arch=native</userinput></screen>
+
+    <variablelist>
+      <title>The meaning of the configure option:</title>
+
+      <varlistentry>
+        <term><parameter>--with-gcc-arch=native</parameter></term>
+        <listitem>
+          <para>Ensure gcc optimizes for the current system.  If this
+          is not specified, the system is guessed and the code generated
+          may not be correct for some systems.  If the generated code
+          will be copied from the native system to a less capable 
+          system, use the less capable system as a parameter. For details 
+          about alternative system types, see <ulink 
+          url='https://gcc.gnu.org/onlinedocs/gcc-8.1.0/gcc/x86-Options.html'>
+          the x86 options in the gcc manual</ulink>.</para>
+        </listitem>
+      </varlistentry>
+
+    </variablelist>
 
     <para>Compile the package:</para>
 
-- 
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