Avoid using sinf() (which is C99) in favor of sin()

This pull request mirrors ScummVM commit bb7930cf:
https://github.com/scummvm/scummvm/commit/bb7930cf9c0adf8e64b1245655ada2ec1d5910ef

In essence, this removes the usage of sinf() (which is C99) and replaces it with regular sin():
http://en.cppreference.com/w/c/numeric/math/sin

There are no real functional changes, but this removes the usage of this C99 function, which in turn fixes compilation with some older toolchains, namely the older PPC OSX toolchain.

Similar changes have been made in other projects, such as gtk+:
https://mail.gnome.org/archives/commits-list/2011-January/msg00223.html