Cross-Compiled Linux From Scratch - Version 3.0.0-RC1-x86

Chapter 5. Constructing Cross-Compile Tools

5.15. Cross GCC-4.8.3 - Final

The GCC package contains the GNU compiler collection, which includes the C and C++ compilers.

5.15.1. Installation of GCC Cross Compiler

The following patch contains a number of updates to the 4.8.3 branch by the GCC developers: 

patch -Np1 -i ../gcc-4.8.3-branch_update-1.patch

Make a couple of essential adjustments to GCC's specs to ensure GCC uses our build environment: 

patch -Np1 -i ../gcc-4.8.3-specs-1.patch

Change the StartFile Spec so that GCC looks in /tools: 

echo -en '\n#undef STANDARD_STARTFILE_PREFIX_1\n#define STANDARD_STARTFILE_PREFIX_1 "/tools/lib/"\n' >> gcc/config/linux.h
echo -en '\n#undef STANDARD_STARTFILE_PREFIX_2\n#define STANDARD_STARTFILE_PREFIX_2 ""\n' >> gcc/config/linux.h

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

mkdir -v ../gcc-build
cd ../gcc-build

Prepare GCC for compilation: 

AR=ar LDFLAGS="-Wl,-rpath,/cross-tools/lib" \
    ../gcc-4.8.3/configure --prefix=/cross-tools \
    --build=${CLFS_HOST} --target=${CLFS_TARGET} --host=${CLFS_HOST} \
    --with-sysroot=${CLFS} --with-local-prefix=/tools \
    --with-native-system-header-dir=/tools/include --disable-nls \
    --enable-shared --disable-static --enable-languages=c,c++ \
    --enable-__cxa_atexit --enable-c99 \
    --enable-long-long --enable-threads=posix --disable-multilib \
    --with-mpc=/cross-tools --with-mpfr=/cross-tools --with-gmp=/cross-tools \
    --with-cloog=/cross-tools --with-isl=/cross-tools --with-system-zlib \
    --enable-checking=release --enable-libstdcxx-time

The meaning of the new configure options:

--enable-languages=c,c++

This option ensures that only the C and C++ compilers are built.

--enable-__cxa_atexit

This option allows use of __cxa_atexit, rather than atexit, to register C++ destructors for local statics and global objects and is essential for fully standards-compliant handling of destructors. It also affects the C++ ABI and therefore results in C++ shared libraries and C++ programs that are interoperable with other Linux distributions.

--enable-c99

Enable C99 support for C programs.

--enable-long-long

Enables long long support in the compiler.

--enable-threads=posix

This enables C++ exception handling for multi-threaded code.

--enable-libstdcxx-time

This enables link-time checks for the availability of clock_gettime clocks, and nanosleep and sched_yield functions, in the C library.

Continue with compiling the package: 

make AS_FOR_TARGET="${CLFS_TARGET}-as" \
    LD_FOR_TARGET="${CLFS_TARGET}-ld"

Install the package: 

make install

Details on this package are located in Section 10.19.2, “Contents of GCC.”