Now that the temporary C libraries have been installed, all tools compiled in the rest of this chapter should be linked against these libraries. In order to accomplish this, the linker and the compiler's specs file need to be adjusted.

The linker, adjusted at the end of the first pass of Binutils, needs to be renamed so that it can be properly found and used. First, backup the original linker, then replace it with the adjusted linker. We'll also create a link to its counterpart in /tools/$(gcc -dumpmachine)/bin

mv -v /tools/bin/{ld,ld-old}
mv -v /tools/$(gcc -dumpmachine)/bin/{ld,ld-old}
mv -v /tools/bin/{ld-new,ld}
ln -sv /tools/bin/ld /tools/$(gcc -dumpmachine)/bin/ld

From this point onwards, everything will link only against the libraries in /tools/lib.

The next task is to point GCC to the new dynamic linker. This is done by dumping GCC's “specs” file to a location where GCC will look for it by default. A simple sed substitution then alters the dynamic linker that GCC will use:

SPECFILE=`dirname $(gcc -print-libgcc-file-name)`/specs &&
gcc -dumpspecs > $SPECFILE &&
sed 's@^/lib/ld-linux.so.2@/tools&@g' $SPECFILE > tempspecfile &&
mv -vf tempspecfile $SPECFILE &&
unset SPECFILE

It is recommended that the above command be copy-and-pasted in order to ensure accuracy. Alternatively, the specs file can be edited by hand. This is done by replacing every occurrence of “/lib/ld-linux.so.2” with “/tools/lib/ld-linux.so.2”

Be sure to visually inspect the specs file in order to verify the intended changes have been made.

During the build process, GCC runs a script (fixincludes) that scans the system for header files that may need to be fixed (they might contain syntax errors, for example), and installs the fixed versions in a private include directory. There is a possibility that, as a result of this process, some header files from the host system have found their way into GCC's private include directory. As the rest of this chapter only requires the headers from GCC and Glibc, which have both been installed at this point, any “fixed” headers can safely be removed. This helps to avoid any host headers polluting the build environment. Run the following commands to remove the header files in GCC's private include directory (you may find it easier to copy and paste these commands, rather than typing them by hand, due to their length):

GCC_INCLUDEDIR=`dirname $(gcc -print-libgcc-file-name)`/include &&
find ${GCC_INCLUDEDIR}/* -maxdepth 0 -xtype d -exec rm -rvf '{}' \; &&
rm -vf `grep -l "DO NOT EDIT THIS FILE" ${GCC_INCLUDEDIR}/*` &&
unset GCC_INCLUDEDIR