Clang doesn't support the pragma, but does support the attribute.
Update the existing patch to do things this way.

With previous versions of lame, this hasn't been an issue, because
if one doesn't pass any -march flag, clang defaults to pentium4 as
target for i386 targets, and there both sse and sse2 are available
by default.

Since lame 3.100, lame now passes -march=i686 even for clang, which
disables SSE by default, requiring the per-function enabling to
actually work.