MTD 248-645A Bedienungsanleitung PDF herunterladen (Seite 60)

Linux From Scratch - Version 7.0

5.7. Glibc-2.14.1

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: 5.5 SBU

Required disk space: 501 MB

5.7.1. Installation of Glibc

Fix a bug that prevents Glibc from building with GCC-4.6.1:

patch -Np1 -i ../glibc-2.14.1-gcc_fix-1.patch

Also address a header check that fails due to an incomplete build environment at this point:

patch -Np1 -i ../glibc-2.14.1-cpuid-1.patch

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-2.14.1/configure --prefix=/tools \

--host=$LFS_TGT --build=$(../glibc-2.14.1/scripts/config.guess) \

--disable-profile --enable-add-ons \

--enable-kernel=2.6.25 --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-2.14.1/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.

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MTD 248-645A Bedienungsanleitung Seite 60