* config/sparc/sol2-64.h: Move ...
* config/sparc/default-64.h: ... to here. Update comment.
* config.gcc: Update Solaris sparc to use default-64.h, also
prefix this header into the list on sparc64-*-linux.
* config/sparc/linux64.h (TARGET_DEFAULT): Only override if
TARGET_64BIT_DEFAULT is defined. Remove commented out reference
to MASK_HARD_QUAD.