* config/tc-mips.h (mips_relax_frag): Take segment as argument.

* config/tc-mips.h (mips_relax_frag): Take segment as argument.
(md_relax_frag): Adjust macro.
* config/tc-mips.c (mips_relax_branch): New variable.
(RELAX_BRANCH_ENCODE, RELAX_BRANCH_P, RELAX_BRANCH_LIKELY,
RELAX_BRANCH_LINK, RELAX_BRANCH_TOOBAR): New.
(RELAX_MIPS16_P): Adjust.
(append_insn): Emit branch to non-constant in a frag_var if
branch-relaxation is desirable and possible.
(OPTION_RELAX_BRANCH, OPTION_NO_RELAX_BRANCH): New options.
(OPTION_ELF_BASE): Adjust.
(md_parse_option): Handle new options.
(md_apply_fix3): Update comment on EMBEDDED_PIC conditional
branch relaxation.
(relaxed_branch_length): New function.
(md_estimate_size_before_relax): Handle branch frags.
(mips_relax_frag): Likewise.
(md_convert_frag): Handle branch frags.  Warn if branch is
relaxed.