Xen-unstable 32bit build broken on 64bit systems with multiarch

[Andrew Cooper <andrew.cooper3@citrix.com>]

Hello,

Trying to build 32bit tools on a 64bit multiarch system (Debian Wheezy
in my case) fails.

$ make XEN_TARGET_ARCH=x86_32 -j4
...
/xen-unstable.hg/tools/libxc/../../tools/include  -fPIC -c -o
xc_dom_x86.opic xc_dom_x86.c
gcc  -DPIC -O1 -fno-omit-frame-pointer -m32 -march=i686 -g
-fno-strict-aliasing -std=gnu99 -Wall -Wstrict-prototypes
-Wno-unused-value -Wdeclaration-after-statement
-Wno-unused-but-set-variable  -D__XEN_TOOLS__ -MMD -MF
.xc_cpuid_x86.opic.d  -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE
-fno-optimize-sibling-calls -mno-tls-direct-seg-refs -D_GNU_SOURCE
-I../../xen/common/libelf -Werror -Wmissing-prototypes -I.
-I/local/xen-unstable.hg/tools/libxc/../../tools/include  -fPIC -c -o
xc_cpuid_x86.opic xc_cpuid_x86.c
gcc  -DPIC -O1 -fno-omit-frame-pointer -m32 -march=i686 -g
-fno-strict-aliasing -std=gnu99 -Wall -Wstrict-prototypes
-Wno-unused-value -Wdeclaration-after-statement
-Wno-unused-but-set-variable  -D__XEN_TOOLS__ -MMD -MF
.xenctrl_osdep_ENOSYS.opic.d  -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE
-fno-optimize-sibling-calls -mno-tls-direct-seg-refs -D_GNU_SOURCE
-I../../xen/common/libelf -Werror -Wmissing-prototypes -I.
-I/local/xen-unstable.hg/tools/libxc/../../tools/include  -fPIC -c -o
xenctrl_osdep_ENOSYS.opic xenctrl_osdep_ENOSYS.c
ar rc libxenctrl.a xc_core.o xc_core_x86.o xc_cpupool.o xc_domain.o
xc_evtchn.o xc_gnttab.o xc_misc.o xc_flask.o xc_physdev.o xc_private.o
xc_sedf.o xc_csched.o xc_csched2.o xc_arinc653.o xc_tbuf.o xc_pm.o
xc_cpu_hotplug.o xc_resume.o xc_tmem.o xc_mem_event.o xc_mem_paging.o
xc_mem_access.o xc_memshr.o xc_hcall_buf.o xc_foreign_memory.o
xtl_core.o xtl_logger_stdio.o xc_pagetab.o xc_linux.o xc_linux_osdep.o
gcc    -Wl,-soname -Wl,libxenctrl.so.4.0 -shared -o libxenctrl.so.4.0.0
xc_core.opic xc_core_x86.opic xc_cpupool.opic xc_domain.opic
xc_evtchn.opic xc_gnttab.opic xc_misc.opic xc_flask.opic xc_physdev.opic
xc_private.opic xc_sedf.opic xc_csched.opic xc_csched2.opic
xc_arinc653.opic xc_tbuf.opic xc_pm.opic xc_cpu_hotplug.opic
xc_resume.opic xc_tmem.opic xc_mem_event.opic xc_mem_paging.opic
xc_mem_access.opic xc_memshr.opic xc_hcall_buf.opic
xc_foreign_memory.opic xtl_core.opic xtl_logger_stdio.opic
xc_pagetab.opic xc_linux.opic xc_linux_osdep.opic -ldl -lpthread
ar rc libxenguest.a xg_private.o xc_suspend.o xc_domain_restore.o
xc_domain_save.o xc_offline_page.o xc_hvm_build.o libelf-tools.o
libelf-loader.o libelf-dominfo.o libelf-relocate.o xc_dom_core.o
xc_dom_boot.o xc_dom_elfloader.o xc_dom_bzimageloader.o
xc_dom_binloader.o xc_dom_compat_linux.o xc_dom_x86.o xc_cpuid_x86.o
/usr/bin/ld: i386 architecture of input file `xc_core.opic' is
incompatible with i386:x86-64 output
/usr/bin/ld: i386 architecture of input file `xc_core_x86.opic' is
incompatible with i386:x86-64 output
/usr/bin/ld: i386 architecture of input file `xc_cpupool.opic' is
incompatible with i386:x86-64 output
/usr/bin/ld: i386 architecture of input file `xc_domain.opic' is
incompatible with i386:x86-64 output
/usr/bin/ld: i386 architecture of input file `xc_evtchn.opic' is
incompatible with i386:x86-64 output
/usr/bin/ld: i386 architecture of input file `xc_gnttab.opic' is
incompatible with i386:x86-64 output
/usr/bin/ld: i386 architecture of input file `xc_misc.opic' is
incompatible with i386:x86-64 output
/usr/bin/ld: i386 architecture of input file `xc_flask.opic' is
incompatible with i386:x86-64 output
/usr/bin/ld: i386 architecture of input file `xc_physdev.opic' is
incompatible with i386:x86-64 output
/usr/bin/ld: i386 architecture of input file `xc_private.opic' is
incompatible with i386:x86-64 output
/usr/bin/ld: i386 architecture of input file `xc_sedf.opic' is
incompatible with i386:x86-64 output
/usr/bin/ld: i386 architecture of input file `xc_csched.opic' is
incompatible with i386:x86-64 output
/usr/bin/ld: i386 architecture of input file `xc_csched2.opic' is
incompatible with i386:x86-64 output
/usr/bin/ld: i386 architecture of input file `xc_arinc653.opic' is
incompatible with i386:x86-64 output
/usr/bin/ld: i386 architecture of input file `xc_tbuf.opic' is
incompatible with i386:x86-64 output
/usr/bin/ld: i386 architecture of input file `xc_pm.opic' is
incompatible with i386:x86-64 output
/usr/bin/ld: i386 architecture of input file `xc_cpu_hotplug.opic' is
incompatible with i386:x86-64 output
/usr/bin/ld: i386 architecture of input file `xc_resume.opic' is
incompatible with i386:x86-64 output
/usr/bin/ld: i386 architecture of input file `xc_tmem.opic' is
incompatible with i386:x86-64 output
/usr/bin/ld: i386 architecture of input file `xc_mem_event.opic' is
incompatible with i386:x86-64 output
/usr/bin/ld: i386 architecture of input file `xc_mem_paging.opic' is
incompatible with i386:x86-64 output
/usr/bin/ld: i386 architecture of input file `xc_mem_access.opic' is
incompatible with i386:x86-64 output
/usr/bin/ld: i386 architecture of input file `xc_memshr.opic' is
incompatible with i386:x86-64 output
/usr/bin/ld: i386 architecture of input file `xc_hcall_buf.opic' is
incompatible with i386:x86-64 output
/usr/bin/ld: i386 architecture of input file `xc_foreign_memory.opic' is
incompatible with i386:x86-64 output
/usr/bin/ld: i386 architecture of input file `xtl_core.opic' is
incompatible with i386:x86-64 output
/usr/bin/ld: i386 architecture of input file `xtl_logger_stdio.opic' is
incompatible with i386:x86-64 output
/usr/bin/ld: i386 architecture of input file `xc_pagetab.opic' is
incompatible with i386:x86-64 output
/usr/bin/ld: i386 architecture of input file `xc_linux.opic' is
incompatible with i386:x86-64 output
/usr/bin/ld: i386 architecture of input file `xc_linux_osdep.opic' is
incompatible with i386:x86-64 output
collect2: error: ld returned 1 exit status
make[3]: *** [libxenctrl.so.4.0.0] Error 1
make[3]: *** Waiting for unfinished jobs....
make[3]: Leaving directory `/local/xen-unstable.hg/tools/libxc'


I suspect that the issue is the lack of an -m32 for

gcc    -Wl,-soname -Wl,libxenctrl.so.4.0 -shared -o libxenctrl.so.4.0.0
xc_core.opic xc_core_x86.opic xc_cpupool.opic xc_domain.opic
xc_evtchn.opic xc_gnttab.opic xc_misc.opic xc_flask.opic xc_physdev.opic
xc_private.opic xc_sedf.opic xc_csched.opic xc_csched2.opic
xc_arinc653.opic xc_tbuf.opic xc_pm.opic xc_cpu_hotplug.opic
xc_resume.opic xc_tmem.opic xc_mem_event.opic xc_mem_paging.opic
xc_mem_access.opic xc_memshr.opic xc_hcall_buf.opic
xc_foreign_memory.opic xtl_core.opic xtl_logger_stdio.opic
xc_pagetab.opic xc_linux.opic xc_linux_osdep.opic -ldl -lpthread

I have tried a few ideas but not managed to get a successful build. 
Does anyone with more knowledge in this area have any suggestions?

~Andrew