%general-entities; ]> glibc &glibc-version;
&glibc-url;
 Glibc-&glibc-version; Glibc tools <xi:include xmlns:xi="http://www.w3.org/2003/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 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. case `uname -m` in i?86) echo "CFLAGS += -march=i486 -mtune=native" > configparms ;; esac Next, prepare Glibc for compilation: ../glibc-&glibc-version;/configure --prefix=/tools \ --host=$LFS_TGT --build=$(../glibc-&glibc-version;/scripts/config.guess) \ --disable-profile --enable-add-ons \ --enable-kernel=2.6.0 --with-headers=/tools/include \ libc_cv_forced_unwind=yes libc_cv_c_cleanup=yes The meaning of the configure options: --host=$LFS_TGT, --build=$(../glibc-&glibc-version;/scripts/config.guess) 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 /tools. --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-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. libc_cv_forced_unwind=yes The build requires support for forced unwind, but because it is being cross compiled, it cannot auto detect it. Setting this variable on the command line explicitly tells the configure script that support is available. libc_cv_c_cleanup=yes The build also requires support for C cleanup handling, which it cannot auto detect when being cross compiled. Enable it explicitly. 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 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 Install the package: make install <para>Details on this package are located in <xref linkend="contents-glibc" role="."/></para> </sect2> </sect1>