This is PR30442.
Previously we were failed to parce complex expressions like:
foo : { *(SORT_BY_NAME(bar) zed) }

Main idea of patch that globs and excludes can be wrapped in a SORT.
There is a difference in semanics of ld/gold:
ld likes:
*(SORT(EXCLUDE_FILE (*file1.o) .foo.1))

gold likes:
*(EXCLUDE_FILE (*file1.o) SORT(.foo.1))

Patch implements ld grammar, complex expressions like 
next is not a problem anymore:
.abc : { *(SORT(.foo.* EXCLUDE_FILE (*file1.o) .bar.*) .bar.*) }


Differential revision: https://reviews.llvm.org/D24758

llvm-svn: 282078