gcc: enable multilib for target gcc

- add a task to setup multilib configuration for target gcc
- this commit adapts Nitin Kamble's work to gcc 4.7
- use a hash for storing arch-dependent multilib options
- patch gcc in order to use the multilib config files from the
build directory

Tests:
root@qemux86-64:~# gcc -m64 t.c -o t
root@qemux86-64:~# file t
t: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), dynamically linked (uses shared libs), for GNU/Linux 2.6.16, not stripped
root@qemux86-64:~# ./t
Hello World !
root@qemux86-64:~# gcc -m32 t.c -o t
root@qemux86-64:~# file t
t: ELF 32-bit LSB executable, Intel 80386, version 1 (SYSV), dynamically linked (uses shared libs), for GNU/Linux 2.6.16, not stripped
root@qemux86-64:~# ./t
Hello World !

[YOCTO #1369]

(From OE-Core rev: b26819c85881e82ee1b5c68840011e78c321f18e)

Signed-off-by: Constantin Musca <constantinx.musca@intel.com>
Signed-off-by: Saul Wold <sgw@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

1 files changed, 2 insertions, 1 deletions

diff --git a/meta/recipes-devtools/gcc/gcc-configure-common.inc b/meta/recipes-devtools/gcc/gcc-configure-common.inc
index 4eb59fd583..b87ea62570 100644
--- a/meta/recipes-devtools/gcc/gcc-configure-common.inc
+++ b/meta/recipes-devtools/gcc/gcc-configure-common.inc
@@ -1,3 +1,4 @@
+require gcc-multilib-config.inc
 #
 # Build the list of lanaguages to build.
 #
@@ -25,7 +26,7 @@ EXTRA_OECONF_PATHS ?= ""
 EXTRA_OECONF_INITIAL ?= ""
 EXTRA_OECONF_INTERMEDIATE ?= ""
 
-GCCMULTILIB = "--disable-multilib"
+GCCMULTILIB ?= "--disable-multilib"
 GCCTHREADS ?= "posix"
 
 EXTRA_OECONF = "${@['--enable-clocale=generic', ''][d.getVar('USE_NLS', True) != 'no']} \