* math/Makefile (calls): Add s_ldexp, s_frexp, s_modf.
These functions are traditionally duplicated in libc and libm.
Go with the flow.
# These functions are in libc instead of libm because __printf_fp
# calls them, so any program using printf will need them linked in,
# and we don't want to have to link every program with -lm.
-calls = s_isinf s_isnan
+calls = s_isinf s_isnan s_frexp s_ldexp s_modf
routines = $(calls) $(calls:=f) $(long-c-$(long-double-fcts))
long-c-yes = $(calls:=l)
distribute += $(long-c-yes:=.c)