Do not generate unwind info in asm functions if _STANDALONE is defined.
The .fnend op causes the assembler to emit RELOC references to unwind
support functions that don't exist in libstand.


git-svn-id: svn+ssh://svn.freebsd.org/base/head@270930 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f