We made sure to emit emms before potentially calling/returning to
 applicate code, but not before calling libc code.
It turns out musl libc's malloc/free implementation use floating
 point, so they don't work correctly unless we do.
Add some extra calls to make sure the FPU is in the proper state
 any place we might potentially call malloc or free.

Thanks to Rune (ztsdztsd on Trac) for the report.

Fixes #2287