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Thomas Petazzoni 50ac5f9a57 Support multilib variants in sub-subdirectories
When an external toolchain has multiple variants organized in
sub-directories, Buildroot only copies the selected sysroot and not
all sysroots. In order to make this work, Buildroot creates a symbolic
link of the name of the original selected sysroot to the main sysroot
to trick the compiler so that it finds its libraries at the expected
location.

I.e, if the toolchain as the following organization (example take on
the ARM CodeSourcery toolchain) :

     .	    	for ARMv5T
     armv4  	for ARMv4T
     thumb2 	for ARMv7-A/Thumb

and ARMv4T is selected, then Buildroot will copy the contents of
armv4t/ from the toolchain into its $(STAGING_DIR) and then create a
$(STAGING_DIR)/armv4t symbolic link to $(STAGING_DIR).

However, our logic to do so only works when there was one directory
level for multilib sysroots. But in the MIPS CodeSourcery toolchain
there are multiple levels. For example, the MIPS16 soft-float
little-endian sysroot variant is in mips16/soft-float/el/ compared to
the main sysroot.

This patch improves our logic to support this case. The logic is a bit
more complicated as we don't want to create a symbolic link to an
absolute path, but a symbolic link to a relative path, because we want
the host/ directory to be relocatable.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
2012-03-01 20:26:36 +01:00
board
boot barebox: add 2012.02, remove 2011.11 2012-02-06 23:25:10 +01:00
configs
docs Update copyright year 2012-03-01 14:04:54 +01:00
fs
linux
package Merge branch 'next' 2012-03-01 14:05:41 +01:00
support pkg-stats: update list of packages to be skipped 2012-02-26 19:46:58 +01:00
target Add the Atom processor in the list of supported x86/x86_64 processors 2012-03-01 20:26:36 +01:00
toolchain Support multilib variants in sub-subdirectories 2012-03-01 20:26:36 +01:00
.defconfig buildroot: get rid of s390 support 2009-01-12 14:36:14 +00:00
.gitignore
CHANGES kickoff 2012.05 development cycle 2012-03-01 14:03:39 +01:00
Config.in Add basic config infrastructure for host utilities 2012-02-02 20:54:19 +01:00
COPYING clarify license and fix website license link 2009-05-08 09:29:41 +02:00
Makefile Merge branch 'next' 2012-03-01 14:05:41 +01:00

To build and use the buildroot stuff, do the following:

1) run 'make menuconfig'
2) select the packages you wish to compile
3) run 'make'
4) wait while it compiles
5) Use your shiny new root filesystem. Depending on which sort of
    root filesystem you selected, you may want to loop mount it,
    chroot into it, nfs mount it on your target device, burn it
    to flash, or whatever is appropriate for your target system.

You do not need to be root to build or run buildroot.  Have fun!

Offline build:
==============

In order to do an offline-build (not connected to the net), fetch all
selected source by issuing a
$ make source

before you disconnect.
If your build-host is never connected, then you have to copy buildroot
and your toplevel .config to a machine that has an internet-connection
and issue "make source" there, then copy the content of your dl/ dir to
the build-host.

Building out-of-tree:
=====================

Buildroot supports building out of tree with a syntax similar
to the Linux kernel. To use it, add O=<directory> to the
make command line, E.G.:

$ make O=/tmp/build

And all the output files (including .config) will be located under /tmp/build.

More finegrained configuration:
===============================

You can specify a config-file for uClibc:
$ make UCLIBC_CONFIG_FILE=/my/uClibc.config

And you can specify a config-file for busybox:
$ make BUSYBOX_CONFIG_FILE=/my/busybox.config

To use a non-standard host-compiler (if you do not have 'gcc'),
make sure that the compiler is in your PATH and that the library paths are
setup properly, if your compiler is built dynamically:
$ make HOSTCC=gcc-4.3.orig HOSTCXX=gcc-4.3-mine

Depending on your configuration, there are some targets you can use to
use menuconfig of certain packages. This includes:
$ make HOSTCC=gcc-4.3 linux-menuconfig
$ make HOSTCC=gcc-4.3 uclibc-menuconfig
$ make HOSTCC=gcc-4.3 busybox-menuconfig

Please feed suggestions, bug reports, insults, and bribes back to the
buildroot mailing list: buildroot@uclibc.org