source: BOOK/cross-tools/x86_64/flags.xml @ 6bb43b3

<?xml version="1.0" encoding="ISO-8859-1"?>
<!DOCTYPE sect1 PUBLIC "-//OASIS//DTD DocBook XML V4.4//EN"
  "http://www.oasis-open.org/docbook/xml/4.4/docbookx.dtd" [
  <!ENTITY % general-entities SYSTEM "../../general.ent">
  %general-entities;
]>

<sect1 id="ch-cross-tools-flags">
  <?dbhtml filename="flags.html"?>

  <title>Build Flags</title>

  <para os="a">We will need to setup target specific flags for the compiler
  and linkers.</para>

<screen os="b"><userinput>export BUILD32="-m32"
export BUILD64="-m64"</userinput></screen>

  <para os="c">You will need to set your host target triplet for 32 bits:</para>

<screen os="d"><userinput>export LFS_TARGET32="i686-pc-linux-gnu"</userinput></screen>

  <para os="e">Let's perform a sanity check to prevent build issues. If our LFS_HOST matches our
  target, we will get some failures during our cross-compile:</para>

<screen os="f"><userinput>if [ "${LFS_HOST}" = "${LFS_TARGET32}" ]; then \
  echo "Host and Target can't be the same." ; fi</userinput></screen>

  <para os="g">If the above test gave you "Host and Target can't be the same", you will need to change your LFS_HOST to a
  a different target triplet:</para>

<screen os="h"><userinput>export LFS_HOST="`echo ${MACHTYPE} | sed -e 's/unknown/cross/g' -e 's/-pc-/-cross-/g'`"</userinput></screen>

  <para os="i">Lets add the build flags to <filename>~/.bashrc</filename> to
  prevent issues if we stop and come back later.</para>

<screen os="j"><userinput>echo export BUILD32=\""${BUILD32}\"" &gt;&gt; ~/.bashrc
echo export BUILD64=\""${BUILD64}\"" &gt;&gt; ~/.bashrc
echo export LFS_TARGET32=\""${LFS_TARGET32}\"" &gt;&gt; ~/.bashrc
echo export LFS_HOST=\""${LFS_HOST}\"" &gt;&gt; ~/.bashrc</userinput></screen>

</sect1>