Copy head@r302406 to stable/11 as part of the 11.0-RELEASE cycle.
Prune svn:mergeinfo from the new branch, as nothing has been merged
here.

Additional commits post-branch will follow.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Remove functions from softfloat's Symbol.map that don't need to be exported.
Also use the proper number of underscores for internal names. (Changing
the names should be fine, since apparently the symbols are currently
unused.)

Use C comments since we now preprocess these files with CPP.

Add symbol maps and initial symbol version definitions to libc.

Reviewed by: davidxu