Always provide declarations of long double math functions when
!_LIBC
appears to fix the problem glibc-arm-mathdefs.patch tries to work
around. It is a simple patch which easily backports to 2.14.7.
Yes, the "correct" fix for glibc-arm-mathdefs is not the patch I
originally put in, but an alternate (upstream?) one that just maps the
declarations to existing functions.