newlib's libc now has dependencies on libm

[Richard Earnshaw <Richard dot Earnshaw at buzzard dot freeserve dot co dot uk>]

I've just seen a sudden large increase in the number of gcc testsuite
failures for ARM after updating my newlib sources.  It looks like libc
has quietly (probably erroneously) grown a link-time dependency on libm:

libc.a:lib_a-strtod.o:         U __fpclassifyd
libc.a:lib_a-svfprintf.o:         U __fpclassifyd
libc.a:lib_a-svfscanf.o:         U __fpclassifyd
libc.a:lib_a-svfwprintf.o:         U __fpclassifyd
libc.a:lib_a-svfwscanf.o:         U __fpclassifyd
libc.a:lib_a-vfprintf.o:         U __fpclassifyd
libc.a:lib_a-vfscanf.o:         U __fpclassifyd
libc.a:lib_a-vfwprintf.o:         U __fpclassifyd
libc.a:lib_a-vfwscanf.o:         U __fpclassifyd
libc.a:lib_a-wcstod.o:         U __fpclassifyd

libm.a:lib_a-s_fpclassify.o:00000000 T __fpclassifyd


My guess is that this was caused by the following change:

2009-06-16  Craig Howland <howland@LGSInnovations.com>

        * libc/include/math.h:  Simplify fpclassify, isinf, isnan, and signbit
        macros to remove un-necessary extension use.  isinf and isnan also
        changed to use fpclassify.  isfinite macro modified to run faster by
        only calling fpclassify once instead of possibly twice.