WIP: Migrate Wiki content over to src/docs

docs/linux_build32_on64.md

+_If you're looking for building a 64 bit Chromium, try LinuxChromium64_
+
+_OBSOLETE: Building 32-bit Chromium on 64-bit Linux is no longer officially supported. The "32-bit compatibility libs" instructions probably won't work. The chroot instructions are your best bet, but it is not actively tested or maintained._

[Bons, 2015/08/20 20:16:50]

delete due to this being obsolete

+
+## Introduction
+On at least Ubuntu Hardy, there is poor support for building 32-bit software.  It seems it's blocked on "multiarch" support in Debian which is a grand solution to the problem but far off in the future.  (See, for example [bug 492453](http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=492453).) So in the interim, we have some hacks that seem to work so far.
+
+Even a successful build will likely have issues: see Linux64BitIssues.
+
+## What are the Prerequisites
+LinuxBuildInstructionsPrerequisites has an up-to-date list of prerequisite packages needed for building chrome, as well as instructions for automatically installing the prerequisites.
+
+The script on that page is based on  a [script on the Ubuntu forums](http://ubuntuforums.org/showthread.php?t=474790) that helps automate installing 32-bit libs on a 64-bit system.
+
+## Manual Setup on Ubuntu/Debian
+  1. Go to [LinuxBuildInstructionsPrerequisites#Automated\_Setup](LinuxBuildInstructionsPrerequisites#Automated_Setup.md).
+  1. Manually run that script.
+
+## Manual Setup on openSUSE
+(Tested on openSUSE 11.1 x86\_64)
+This can be incomplete list.
+
+### Packages
+gcc-32bit
+glibc-devel-32bit
+libgio-2\_0-0-32bit
+gtk2-32bit
+libatk-1\_0-0-32bit
+gtk2-32bit
+pango-32bit
+pango-32bit
+pango-32bit
+gtk2-32bit
+cairo-32bit
+freetype2-32bit
+fontconfig-32bit
+libstdc++43-32bit
+xorg-x11-libX11-devel-32bit
+xorg-x11-libXrender-devel-32bit
+xorg-x11-libXext-devel-32bit
+libasound2-32bit
+
+### Symlinks
+
+```
+#!/bin/bash
+cd /usr/lib
+for lib in gio-2.0 gdk-x11-2.0 atk-1.0 gdk_pixbuf-2.0 \
+           pangocairo-1.0 pango-1.0 pangoft2-1.0 \
+           gobject-2.0 gmodule-2.0 glib-2.0 gtk-x11-2.0; do
+  ln -s -f lib$lib.so.0 lib$lib.so
+done
+ln -s -f libcairo.so.2 libcairo.so
+ln -s -f libfreetype.so.6 libfreetype.so
+ln -s -f libfontconfig.so.1 libfontconfig.so
+ln -s -f libstdc++.so.6 libstdc++.so
+ln -s -f libgthread-2.0.so.0.1800.2 libgthread-2.0.so
+ln -s -f libgconf-2.so.4.1.5 libgconf-2.so
+ln -s -f libasound.so.2 libasound.so
+
+ln -s -f /lib/libz.so.1 /lib/libz.so
+ln -s -f /lib/libgcc_s.so.1 /lib/libgcc_s.so
+```
+
+### Useful commands
+To find libs you need, you can use locate, zypper and rpm, examples:
+```
+$locate libgcc.a
+/usr/lib64/gcc/x86_64-suse-linux/4.3/libgcc.a
+
+$rpm -q -f /usr/lib64/gcc/x86_64-suse-linux/4.3/libgcc.a
+gcc43-4.3.3_20081022-9.8
+
+$sudo zypper se gcc43
+...
+  | gcc43-32bit         | The GNU C Compiler and Support Files          | package
+...
+
+for more info use man
+```
+
+## Compiling
+To compile using the Linux make build, set `GYP_DEFINES=target_arch=ia32` and then (re)build the Makefiles:
+```
+gclient runhooks --force
+```
+After that, you can use `make` to compile as described in the [Linux Build Instructions](http://code.google.com/p/chromium/wiki/LinuxBuildInstructions).
+
+
+### Ubuntu 32bit chroot on 64bit system
+
+The [build/install-build-deps.sh](http://src.chromium.org/svn/trunk/src/build/install-build-deps.sh) script installs all the 32bit compatibility libraries to build a 32bit binary on a 64bit Ubuntu system. But it is often easier and more reliable to develop in a real 32bit environment, instead of building against compatibility libraries.
+
+This can be done by setting up a 32bit chroot on a machine that is otherwise running a 64bit distribution.
+
+To do so, run the [build/install-chroot.sh](http://src.chromium.org/svn/trunk/src/build/install-chroot.sh) script. It asks you which environment to install. Pick any recent Ubuntu distribution (e.g. lucid) and select a 32bit installation.
+
+Optionally, change your chrome/src/out directory to be a symbolic link pointing to $HOME/chroot. This way, you can build both 32bit and 64bit versions from the same source tree.
+
+Now, install all build-prerequisites in the 32bit chroot:
+
+```
+  lucid32 build/install-build-deps.sh
+```
+
+Reset your makefiles, if they are still configured for a 64bit build environment:
+
+```
+  lucid32 gclient runhooks
+```
+
+And build Chromium using the development tools in the chroot environment:
+
+```
+  lucid32 make chrome
+```
+
+Run the resulting binary as you would normally do:
+
+```
+   lucid32 out/Debug/chrome
+```
+
+Before building a 64bit version in the same source tree, don't forget to reset your makefiles again
+
+```
+   gclient runhooks && make chrome
+```