Linux From Scratch - Version 6.4

Chapter 5. Constructing a Temporary System

5.7. Glibc-2.8-20080929

The Glibc package contains the main C library. This library provides the basic routines for allocating memory, searching directories, opening and closing files, reading and writing files, string handling, pattern matching, arithmetic, and so on.

Approximate build time: 7.6 SBU
Required disk space: 407 MB

5.7.1. Installation of Glibc

Fix a potential issue if /etc/ld.so.preload is used on the host system. 

sed -i 's@/etc/ld.so.preload@/tools/etc/ld.so.preload@' elf/rtld.c

The Glibc documentation recommends building Glibc outside of the source directory in a dedicated build directory: 

mkdir -v ../glibc-build
cd ../glibc-build

Because Glibc no longer supports i386, its developers say to use the compiler flag -march=i486 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 “CFLAGS”. 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 configparms. The -mtune=native flag is also necessary to reset a reasonable value for -mtune that is changed when setting -march. 

echo "CFLAGS += -march=i486 -mtune=native" > configparms

Next, prepare Glibc for compilation: 

../glibc-2.8-20080929/configure --prefix=/tools \
    --disable-profile --enable-add-ons \
    --enable-kernel=2.6.0 --with-binutils=/tools/bin \
    --without-gd --with-headers=/tools/include \
    --without-selinux

The meaning of the configure options:

--disable-profile

This builds the libraries without profiling information. Omit this option if profiling on the temporary tools is necessary.

--enable-add-ons

This tells Glibc to use the NPTL add-on as its threading library.

--enable-kernel=2.6.0

This tells Glibc to compile the library with support for 2.6.x Linux kernels.

--with-binutils=/tools/bin

While not required, this switch ensures that there are no errors pertaining to which Binutils programs get used during the Glibc build.

--without-gd

This prevents the build of the memusagestat program, which insists on linking against the host's libraries (libgd, libpng, libz, etc.).

--with-headers=/tools/include

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.

--without-selinux

When building from hosts that include SELinux functionality (e.g., Fedora Core 3), Glibc will build with support for SELinux. As the LFS tools environment does not contain support for SELinux, a Glibc compiled with such support will fail to operate correctly.

During this stage the following warning might appear: 

configure: WARNING:
*** These auxiliary programs are missing or
*** incompatible versions: msgfmt
*** some features will be disabled.
*** Check the INSTALL file for required versions.

The missing or incompatible msgfmt program is generally harmless, but it can sometimes cause issues when running the test suite. This msgfmt program is part of the Gettext package which the host distribution should provide. If msgfmt is present but deemed incompatible, upgrade the host system's Gettext package or continue without it and see if the test suite runs without problems regardless.

Compile the package: 

make

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.

The install stage of Glibc will issue a harmless warning at the end about the absence of /tools/etc/ld.so.conf. Prevent this warning with: 

mkdir -v /tools/etc
touch /tools/etc/ld.so.conf

Install the package: 

make install

Different countries and cultures have varying conventions for how to communicate. These conventions range from the format for representing dates and times to more complex issues, such as the language spoken. The “internationalization” of GNU programs works by locale.

[Note]

Note

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 Section 6.9, “Glibc-2.8-20080929.”

Details on this package are located in Section 6.9.4, “Contents of Glibc.”