[Sun C++/Linux/x86] assembler error on xchg in i86/atomic.s

All Sun C++ 5.9 builds on Linux/x86 are failing with the error below:

...
gmake: Entering directory `$(BUILDDIR)/lib'
CC -c -D_RWSTDDEBUG -I$(TOPDIR)/include -I$(BUILDDIR)/include -library=%none -g -m32 +w -errtags -erroff=hidef -KPIC $(TOPDIR)/src/assert.cpp
CC -c -D_RWSTDDEBUG -I$(TOPDIR)/include -I$(BUILDDIR)/include -library=%none -g -m32 +w -errtags -erroff=hidef -KPIC $(TOPDIR)/src/atomic-cxx.S
Assembler:
"$(TOPDIR)/src/i86/atomic.s", line 60 : Syntax error
Near line: " xchg %al, (%ecx)"
gmake: *** [atomic-cxx.o] Error 127
gmake: Leaving directory `$(BUILDDIR)/lib'
Command exited with non-zero status 2