Buildworld broken at lib/msun

cc -O -pipe -mcpu=pentiumpro -D_IEEE_LIBM -D_ARCH_INDIRECT=i387_ -std=gnu99   -c i387_e_acos.S -o i387_e_acos.o
{standard input}: Assembler messages:
{standard input}:19: Error: junk `(__ieee754_acos)' after expression
{standard input}:19: Error: junk `(__ieee754_acos)' after expression
*** Error code 1

Now, i387_e_acos.S hasn't changed, so something else is wrong.

When I 'cd /usr/src/lib/msun' and do a make from there it compiles
and assembles just fine.  This maybe smells like one of the usual
suspects like awk, sed, sh, and their surly gang ;-)

sed was just repaired yesterday, for example.  Maybe it still needs
another tweak?