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<?xml version="1.0" encoding="ISO-8859-1"?>
<!DOCTYPE sect1 PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
"http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" [
<!ENTITY % general-entities SYSTEM "../general.ent">
%general-entities;
]>
<sect1 id="ch-tools-glibc" role="wrap">
<?dbhtml filename="glibc.html"?>
<sect1info condition="script">
<productname>glibc</productname>
<productnumber>&glibc-version;</productnumber>
<address>&glibc-url;</address>
</sect1info>
<title>Glibc-&glibc-version;</title>
<indexterm zone="ch-tools-glibc">
<primary sortas="a-Glibc">Glibc</primary>
<secondary>tools</secondary>
</indexterm>
<sect2 role="package">
<title/>
<xi:include xmlns:xi="http://www.w3.org/2001/XInclude"
href="../chapter06/glibc.xml"
xpointer="xpointer(/sect1/sect2[1]/para[1])"/>
<segmentedlist>
<segtitle>&buildtime;</segtitle>
<segtitle>&diskspace;</segtitle>
<seglistitem>
<seg>&glibc-ch5-sbu;</seg>
<seg>&glibc-ch5-du;</seg>
</seglistitem>
</segmentedlist>
</sect2>
<sect2 role="installation">
<title>Installation of Glibc</title>
<para>Address a header check that fails due to an incomplete build
environment at this point:</para>
<screen><userinput remap="pre">sed -i 's#$ac_includes_default#\n\n#' sysdeps/i386/configure</userinput></screen>
<para>Fix a path that is hardcoded:</para>
<screen><userinput remap="pre">sed -i 's#/var/db#/tools/var/db#' Makeconfig</userinput></screen>
<para>Fix a bug that prevents Glibc from building with GCC-&gcc-version;:</para>
<screen><userinput remap="pre">patch -Np1 -i ../&glibc-gcc_fix-patch;</userinput></screen>
<para>The Glibc documentation recommends building Glibc outside of the source
directory in a dedicated build directory:</para>
<screen><userinput remap="pre">mkdir -v ../glibc-build
cd ../glibc-build</userinput></screen>
<para>Because Glibc no longer supports i386, its developers say to use the
compiler flag <parameter>-march=i486</parameter> when building it for x86
machines. There are several ways to accomplish that, but testing shows that
the flag is best placed inside the build variable <quote>CFLAGS</quote>.
Instead of overriding completely what Glibc's internal build system uses
for CFLAGS, append the new flag to the existing contents of CFLAGS by
making use of the special file <filename>configparms</filename>. The
-mtune=native flag is also necessary to reset a reasonable value for -mtune
that is changed when setting -march.</para>
<screen><userinput remap="configure">case `uname -m` in
i?86) echo "CFLAGS += -march=i486 -mtune=native" > configparms ;;
esac</userinput></screen>
<para>Next, prepare Glibc for compilation:</para>
<screen><userinput remap="configure">../glibc-&glibc-version;/configure \
--prefix=/tools \
--host=$LFS_TGT \
--build=$(../glibc-&glibc-version;/scripts/config.guess) \
--disable-profile \
--enable-add-ons \
--enable-kernel=2.6.25 \
--with-headers=/tools/include \
libc_cv_forced_unwind=yes \
libc_cv_ctors_header=yes \
libc_cv_c_cleanup=yes</userinput></screen>
<variablelist>
<title>The meaning of the configure options:</title>
<varlistentry>
<term><parameter>--host=$LFS_TGT, --build=$(../glibc-&glibc-version;/scripts/config.guess)</parameter></term>
<listitem>
<para>The combined effect of these switches is that Glibc's build system
configures itself to cross-compile, using the cross-linker and
cross-compiler in <filename class="directory">/tools</filename>.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>--disable-profile</parameter></term>
<listitem>
<para>This builds the libraries without profiling information. Omit
this option if profiling on the temporary tools is necessary.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>--enable-add-ons</parameter></term>
<listitem>
<para>This tells Glibc to use the NPTL add-on as its threading
library.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>--enable-kernel=2.6.25</parameter></term>
<listitem>
<para>This tells Glibc to compile the library with support
for 2.6.25 and later Linux kernels. Workarounds for older
kernels are not enabled.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>--with-headers=/tools/include</parameter></term>
<listitem>
<para>This tells Glibc to compile itself against the headers recently
installed to the tools directory, so that it knows exactly what
features the kernel has and can optimize itself accordingly.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>libc_cv_forced_unwind=yes</parameter></term>
<listitem>
<para>The linker installed during
<xref linkend="ch-tools-binutils-pass1"/> was cross-compiled and as
such cannot be used until Glibc has been installed. This means that
the configure test for force-unwind support will fail, as it relies on
a working linker. The libc_cv_forced_unwind=yes variable is passed in
order to inform <command>configure</command> that force-unwind
support is available without it having to run the test.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>libc_cv_c_cleanup=yes</parameter></term>
<listitem>
<para>Simlarly, we pass libc_cv_c_cleanup=yes through to the
<command>configure</command> script so that the test is skipped and C
cleanup handling support is configured.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>libc_cv_ctors_header=yes</parameter></term>
<listitem>
<para>Simlarly, we pass libc_cv_ctors_header=yes through to the
<command>configure</command> script so that the test is skipped and
gcc constructor support is configured.</para>
</listitem>
</varlistentry>
</variablelist>
<para>During this stage the following warning might appear:</para>
<blockquote>
<screen><computeroutput>configure: WARNING:
*** These auxiliary programs are missing or
*** incompatible versions: msgfmt
*** some features will be disabled.
*** Check the INSTALL file for required versions.</computeroutput></screen>
</blockquote>
<para>The missing or incompatible <command>msgfmt</command> program is
generally harmless. This <command>msgfmt</command> program is part of the
Gettext package which the host distribution should provide.</para>
<para>Compile the package:</para>
<screen><userinput remap="make">make</userinput></screen>
<para>This package does come with a test suite, however, it cannot be
run at this time because we do not have a C++ compiler yet.</para>
<note>
<para>The test suite also requires locale data to be installed in order to run
successfully. Locale data provides information to the system regarding
such things as the date, time, and currency formats accepted and output by
system utilities. If the test suites are not being run in this chapter
(as per the recommendation), there is no need to install the locales now.
The appropriate locales will be installed in the next chapter. To install
the Glibc locales anyway, use instructions from <xref
linkend="ch-system-glibc" role="."/></para>
</note>
<para>Install the package:</para>
<screen><userinput remap="install">make install</userinput></screen>
<caution>
<para>At this point, it is imperative to stop and ensure that the basic
functions (compiling and linking) of the new toolchain are working as
expected. To perform a sanity check, run the following commands:</para>
<screen><userinput>echo 'main(){}' > dummy.c
$LFS_TGT-gcc dummy.c
readelf -l a.out | grep ': /tools'</userinput></screen>
<para>If everything is working correctly, there should be no errors,
and the output of the last command will be of the form:</para>
<screen><computeroutput>[Requesting program interpreter: /tools/lib/ld-linux.so.2]</computeroutput></screen>
<para>Note that <filename class="directory">/tools/lib</filename>, or
<filename class="directory">/tools/lib64</filename> for 64-bit machines
appears as the prefix of the dynamic linker.</para>
<para>If the output is not shown as above or there was no output at all,
then something is wrong. Investigate and retrace the steps to find out
where the problem is and correct it. This issue must be resolved before
continuing on.</para>
<para>Once all is well, clean up the test files:</para>
<screen><userinput>rm -v dummy.c a.out</userinput></screen>
</caution>
<note><para>Building Binutils in the next section will serve as an additional check that
the toolchain has been built properly. If Binutils fails to build, it is an
indication that something has gone wrong with the previous Binutils, GCC, or Glibc
installations.</para></note>
</sect2>
<sect2 role="content">
<title/>
<para>Details on this package are located in
<xref linkend="contents-glibc" role="."/></para>
</sect2>
</sect1>
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