-m32 build of libffi head fails on darwin

[Jack Howarth <howarth dot mailing dot lists at gmail dot com>]

   Currently libffi head can be built on x86_64-apple-darwin14 with
Xcode 6.1 using just...

mkdir build
cd build
../configure

and 'make check' shows...

Native configuration is x86_64-apple-darwin14.1.0

=== libffi tests ===

Schedule of variations:
    unix

Running target unix
Using /sw/share/dejagnu/baseboards/unix.exp as board description file
for target.
Using /sw/share/dejagnu/config/unix.exp as generic interface file for target.
Using ../../testsuite/config/default.exp as tool-and-target-specific
interface file.
Running ../../testsuite/libffi.call/call.exp ...
FAIL: libffi.call/unwindtest.cc -W -Wall -O0 execution test
FAIL: libffi.call/unwindtest.cc -W -Wall -O1 execution test
FAIL: libffi.call/unwindtest.cc -W -Wall -O2 execution test
FAIL: libffi.call/unwindtest.cc -W -Wall -O3 execution test
FAIL: libffi.call/unwindtest.cc -W -Wall -Os execution test
Running ../../testsuite/libffi.complex/complex.exp ...
Running ../../testsuite/libffi.go/go.exp ...

=== libffi Summary ===

# of expected passes 2210
# of unexpected failures 5

Using...

../configure CC=gcc-fsf-5.0 CXX=g++-fsf-5.0

to avoid the clang compilers produces pristine test suite results...

Native configuration is x86_64-apple-darwin14.1.0

=== libffi tests ===

Schedule of variations:
    unix

Running target unix
Using /sw/share/dejagnu/baseboards/unix.exp as board description file
for target.
Using /sw/share/dejagnu/config/unix.exp as generic interface file for target.
Using ../../testsuite/config/default.exp as tool-and-target-specific
interface file.
Running ../../testsuite/libffi.call/call.exp ...
Running ../../testsuite/libffi.complex/complex.exp ...
Running ../../testsuite/libffi.go/go.exp ...

=== libffi Summary ===

# of expected passes 2220

Unfortunately, the -m32 build for both compilers are broken. On system
clang compilers, we get...

libtool: compile:  gcc -DHAVE_CONFIG_H -I. -I.. -I. -I../include
-Iinclude -I../src -I. -I../include -Iinclude -I../src -O2 -g -m32 -MT
src/x86/sysv.lo -MD -MP -MF src/x86/.deps/sysv.Tpo -c
../src/x86/sysv.S  -fno-common -DPIC -o src/x86/.libs/sysv.o
../src/x86/sysv.S:862:16: error: invalid variant 'rel'
 .long LUW0@rel
               ^
../src/x86/sysv.S:884:16: error: invalid variant 'rel'
 .long LUW6@rel
               ^
../src/x86/sysv.S:896:16: error: invalid variant 'rel'
 .long LUW9@rel
               ^
../src/x86/sysv.S:908:17: error: invalid variant 'rel'
 .long LUW12@rel
                ^
../src/x86/sysv.S:936:17: error: invalid variant 'rel'
 .long LUW21@rel
                ^
../src/x86/sysv.S:948:17: error: invalid variant 'rel'
 .long LUW24@rel
                ^
../src/x86/sysv.S:962:17: error: invalid variant 'rel'
 .long LUW27@rel
                ^
../src/x86/sysv.S:981:17: error: invalid variant 'rel'
 .long LUW32@rel
                ^
../src/x86/sysv.S:1005:17: error: invalid variant 'rel'
 .long LUW41@rel
                ^
Makefile:1230: recipe for target 'src/x86/sysv.lo' failed

for

../configure --build=i386-apple-darwin14 --target=i386-apple-darwin14
--host=i386-apple-darwin14 CFLAGS="-O2 -g -m32"
make

whereas for the FSF gcc compilers, we get...

libtool: compile:  gcc-fsf-5.0 -DHAVE_CONFIG_H -I. -I.. -I.
-I../include -Iinclude -I../src -I. -I../include -Iinclude -I../src
-O2 -g -m32 -MT src/x86/sysv.lo -MD -MP -MF src/x86/.deps/sysv.Tpo -c
../src/x86/sysv.S  -fno-common -DPIC -o src/x86/.libs/sysv.o
../src/x86/sysv.S:862:Rest of line ignored. 1st junk character valued 64 (@).
../src/x86/sysv.S:884:Rest of line ignored. 1st junk character valued 64 (@).
../src/x86/sysv.S:896:Rest of line ignored. 1st junk character valued 64 (@).
../src/x86/sysv.S:908:Rest of line ignored. 1st junk character valued 64 (@).
../src/x86/sysv.S:936:Rest of line ignored. 1st junk character valued 64 (@).
../src/x86/sysv.S:948:Rest of line ignored. 1st junk character valued 64 (@).
../src/x86/sysv.S:962:Rest of line ignored. 1st junk character valued 64 (@).
../src/x86/sysv.S:981:Rest of line ignored. 1st junk character valued 64 (@).
../src/x86/sysv.S:1005:Rest of line ignored. 1st junk character valued 64 (@).
Makefile:1230: recipe for target 'src/x86/sysv.lo' failed

Any ideas on how to fix this issue with sysv,S?
                  Jack