Tor 0.2.4.9 fails to compile on EL5.8/x86_64

Compilation of Tor 0.2.4.9 fails with "internal compiler error" pasted below.

All other RPM platforms (EL5/i686; FC16, FC17, EL6 i686/x86_64) compile fine.

Most likely it's really a compiler bug.

  CC     src/common/compat_libevent.o
  AR     src/common/libor-event.a
  CC     src/ext/curve25519_donna/src_common_libcurve25519_donna_a-curve25519-donna-c64.o
src/ext/curve25519_donna/curve25519-donna-c64.c: In function 'curve25519_donna':
src/ext/curve25519_donna/curve25519-donna-c64.c:449: error: unrecognizable insn:
(insn 10003 10002 10004 20 src/ext/curve25519_donna/curve25519-donna-c64.c:259 (parallel [
            (set (reg:CC 17 flags)
                (unspec:CC [
                        (reg:DI 2 cx [orig:375 t$0.894 ] [375])
                        (const_int 2251799813685229 [0x7ffffffffffed])
                    ] 24))
            (set (reg:DI 2 cx [orig:375 t$0.894 ] [375])
                (plus:DI (reg:DI 2 cx [orig:375 t$0.894 ] [375])
                    (const_int 2251799813685229 [0x7ffffffffffed])))
        ]) -1 (nil)
    (nil))
src/ext/curve25519_donna/curve25519-donna-c64.c:449: internal compiler error: in extract_insn, at recog.c:2084
Please submit a full bug report,
with preprocessed source if appropriate.
See <URL:http://bugzilla.redhat.com/bugzilla> for instructions.
Preprocessed source stored into /tmp/ccUNksyy.out file, please attach this to your bugreport.
make[1]: *** [src/ext/curve25519_donna/src_common_libcurve25519_donna_a-curve25519-donna-c64.o] Error 1
make[1]: Leaving directory `/builddir/build/BUILD/tor-0.2.4.9-alpha'
make: *** [all] Error 2