1. Building a cross-compiler

This section shows how to setup a cross compiler to compile on one machine that runs on another machine. While the examples use a host of i686-pc-linux-gnu, these instructions are generic and should work on any platform, subject to the limits of the compiler and assembler.

Prerequisites	What you will need to begin.
Building the Cross Compiler	Step by step instructions.
Additional Libraries	How to deal with non-system libraries.

1.1 Prerequisites

You should be familiar with compiling GCC and glibc before continuing. Building a cross compiler is not difficult, but you should make sure that you have enough experience before attempting this.

You will need GCC and GNU Make to begin. You cannot build a cross-compiler from the compiler that comes with most systems, and several components use GNU Make extensions. You will also need any other the programs to support these builds, like gawk, sed, bison, and friends. If you have don't know what you need, consider reviewing building gcc and glibc awhile before going on.

These instructions assume that you have write access to `/usr/local'. If you do not, you should change the `prefix'. `prefix'/bin should be in your path.

The build requires about 750 MB to complete, and the resulting binaries will consume around 300 MB.

If you are unsure of any of these steps, DO NOT CONTINUE. If a bad option is passed to `configure' or `make', you may OVERWRITE your local C library, or C compiler, leaving your system in an UNUSABLE state. You have been warned.

The following web sites can help you get started:

• http://www.objsw.com/CrossGCC/ Cross-compiler FAQ.
• http://www.gnu.org/manual/ Online manuals for all GNU projects.
• http://sourceware.cygnus.com/ Web sites and mailing lists for the C Library, and assembler as well as some other project.
• http://gcc.gnu.org/ Web site dedicated to the GNU Compiler Collection.
• http://www.cyclic.com/ Home of CVS.

• gcc-core-2.95.2
• binutils-2.9.5.0.22
• egcs-core-1.1.2
• gnumach-CVS
• mig-CVS
• glibc-2.1.2 (with crypt add-on)

1.2 Building the Cross Compiler

To begin, unpack or checkout all of your packages in a directory. Then, create a series of build directories. Your directory should look like this:

$ ls -al
total 21
drwxrwxr-x  14 jbailey  jbailey      1024 Dec 19 11:30 .
drwx------  77 jbailey  jbailey      8192 Dec 19 11:29 ..
drwxrwxr-x   2 jbailey  jbailey      1024 Dec 19 11:29 binutils
drwxrwxr-x   2 jbailey  jbailey      1024 Dec 19 11:30 build.binutils
drwxrwxr-x   2 jbailey  jbailey      1024 Dec 19 11:30 build.egcs
drwxrwxr-x   2 jbailey  jbailey      1024 Dec 19 11:30 build.gcc
drwxrwxr-x   2 jbailey  jbailey      1024 Dec 19 11:30 build.glibc
drwxrwxr-x   2 jbailey  jbailey      1024 Dec 19 11:30 build.gnumach
drwxrwxr-x   2 jbailey  jbailey      1024 Dec 19 11:30 build.mig
drwxrwxr-x   2 jbailey  jbailey      1024 Dec 19 11:29 egcs-1.1.2
drwxrwxr-x   2 jbailey  jbailey      1024 Dec 19 11:29 gcc-2.95.2
drwxrwxr-x   2 jbailey  jbailey      1024 Dec 19 11:30 glibc-2.1.2
drwxrwxr-x   2 jbailey  jbailey      1024 Dec 19 11:29 gnumach
drwxrwxr-x   2 jbailey  jbailey      1024 Dec 19 11:29 mig
$

1. binutils:
   cd build.binutils
   ../binutils/configure --prefix=/usr/local --target=i586-pc-gnu
   make
   make check
   make install
   cd ..

2. egcs: If you ignored the earlier warning not to continue without 750 MB of drive space free and are thinking about deleting the build dirs when you are done, do not delete this one. You will need it again.

   This step depends on some later steps to complete, so will fail with an error. Don't panic.

   
   cd build.egcs
   ../egcs-1.1.2/configure --prefix=/usr/local --target=i586-pc-gnu --with-gnu-as --with-gnu-ld
   make -k
   make -k install
   cd ..

3. gnumach:
   cd build.gnumach
   ../gnumach/configure --build=i686-pc-linux-gnu --host=i586-pc-gnu
   make -k install-headers prefix=/usr/local/i586-pc-gnu
   cd ..

4. mig:
   cd build.mig
   ../mig/configure --target=i586-pc-gnu --host=i686-pc-linux-gnu --prefix=/usr/local
   make
   make install
   cd ..

5. Rename gcc to egcs: This allows the 2 compilers to co-exist on the same system. If you ever want to use egcs instead of gcc for compiling something, set CC=i586-pc-gnu-egcs.

   
   mv /usr/local/bin/i586-pc-gnu-gcc /usr/local/bin/i586-pc-gnu-egcs

6. gcc: If you ignored the earlier warning not to continue without 750 MB of drive space free and are thinking about deleting the build dirs when you are done, do not delete this one. You will need it again.

   This step depends on some later steps to complete, so will fail with an error. Don't panic.

   
   cd build.gcc
   ../gcc-2.95.2/configure --prefix=/usr/local --target=i586-pc-gnu --with-gnu-as --with-gnu-ld
   make -k
   make -k install
   cd ..
   ln -s /usr/local/i586-pc-gnu/ /usr/local/lib/gcc-lib/i586-pc-gnu/2.95.2/i586-pc-gnu

7. hurd:
   ../hurd/configure --build=i686-pc-linux-gnu --host=i586-pc-gnu --prefix=/usr/local/i586-pc-gnu --disable-profile
   make install-headers no_deps=t
   cd ..

8. glibc: The `configure' script in glibc allows you to select all of the add-ons. You should specify them explicitely for the hurd, because linking linuxthreads in by accident will cause problems.

   This is also a bad directory to delete.

   
   cd build.glibc
   ../glibc-2.1.2/configure --without-cvs --enable-add-ons=crypt --build=i686-pc-linux-gnu --host=i586-pc-gnu --prefix= --disable-profile
   make -k install-headers install_root=/usr/local/i586-pc-gnu
   cp ../glibc-2.1.2/include/features.h /usr/local/i586-pc-gnu/include/features.h
   mkdir /usr/local/i586-pc-gnu/include/gnu
   touch /usr/local/i586-pc-gnu/include/gnu/stubs.h
   cd ..

   The stubs file will be correctly overwritten later on when we do the full glibc install. However, the file isn't generated until the last possible moment, so make install-headers doesn't pick it up.

9. egcs: If you deleted egcs before (despite warnings indicating that you shouldn't) you will have to go back and redo the earlier step. However, the install should complete succesfully this time, and this step won't be needed.

   
   cd build.egcs
   make
   make install
   cd ..

10. gcc: If you deleted egcs before (despite warnings indicating that you shouldn't) you will have to go back and redo the earlier step. However, the install should complete succesfully this time, and this step won't be needed.

    
    cd build.gcc
    make
    make install
    cd ..

11. glibc: The compiler is now fully functional and should cheerfully complete the compile.

    
    cd build.glibc
    make
    make install install_root=/usr/local/i586-pc-gnu
    cd ..

12. Fixing libc.so: There is a default instruction for the hurd to tell it where to find some of it's libraries. This will confuse the linker into thinking that the libc is really in `/lib' on your system. Symlinking this file to the real libc.so will solve the problem.

    
    ln -s -f /usr/local/i586-pc-gnu/lib/libc.so.0.2 /usr/local/i586-pc-gnu/lib/libc.so

1.3 Additional Libraries

It should be safe to simply copy any built libraries and headers into appropraite directories under /usr/local/i586-pc-gnu/

Footnotes

(1)

These instructions have not been tested using anything other than the C compiler. It is possible that you could build a cross-C++ (and friends) compiler using these instructions.

(2)

Both egcs-1.1.2 and gcc-2.95.2 are included here because the latest gcc will not compile gnumach or the hurd. This is due to some invalid code in those programs that used to be permissable.

Table of Contents

• 1. Building a cross-compiler
• 1.1 Prerequisites
• 1.2 Building the Cross Compiler
• 1.3 Additional Libraries

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