https://bugzilla.mozilla.org/show_bug.cgi?id=627668

diff -up xulrunner-2.0/mozilla/js/src/Makefile.in.big-endian-jit xulrunner-2.0/mozilla/js/src/Makefile.in
--- xulrunner-2.0/mozilla/js/src/Makefile.in.big-endian-jit	2010-11-04 21:05:48.000000000 +0100
+++ xulrunner-2.0/mozilla/js/src/Makefile.in	2010-11-15 14:17:39.000000000 +0100
@@ -371,7 +371,7 @@ CPPSRCS += 	checks.cc \
 # END enclude sources for V8 dtoa
 #############################################
 
-ifeq (,$(filter-out powerpc sparc,$(TARGET_CPU)))
+ifeq (,$(filter-out powerpc powerpc64 sparc sparc64 s390 s390x,$(TARGET_CPU)))
 
 VPATH +=	$(srcdir)/assembler \
 		$(srcdir)/assembler/wtf \