[patch] Add -static-libquadmath option

[Joseph S. Myers]

Since -static-libquadmath introduces LGPL requirements on redistributing 
the resulting binaries (that you provide source or relinkable object files 
to allow relinking with modified versions of libquadmath) that don't 
otherwise generally apply simply through using GCC to build a program even 
if you link in GCC's other libraries statically, it would seem a good idea 
for the documentation of this option to make that explicit.

-- 
Joseph S. Myers
joseph@codesourcery.com