Log Message:
mold: update to 1.2.1.

Bug fixes and compatibility improvements:

- Various bugs in --gdb-index have been fixed.
- mold now recognizes --thinlto-cache-dir and --thinlto-cache-policy for the
  sake of compatibility with LLVM lld. (7ebd071)
- mold can now handle TLS common symbols. It looks like GCC sometimes creates
  such symbol for a thread-local variable. (cf850f8)
- In some edge cases, mold created a non-versioned symbol and a versioned one
  for the same symbol, even though if one symbol is versioned, all symbols of
  the same name must be versioned. This bug has been fixed. (8298c0a)
- mold used to write a PLT address of a symbol instead of its address to
  .symtab. This bug has been fixed. (e088db7)
- mold can now handle an input file with more than 219 symbols. (f1f2d40)
- /usr/local/libexec/mold/ld is now installed as a relative symlink instead
  of an absolute symlink. (5803c3c)