https://bugs.llvm.org/show_bug.cgi?id=44775
This rule will be implemented by GNU as https://sourceware.org/ml/binutils/2020-02/msg00028.html
It allows us to simplify
```
.section .foo,"o",foo,unique,0
.section .foo,"o",bar,unique,1 # different section
```
as:
```
.section .foo,"o",foo
.section .foo,"o",bar # different section
```
We consider the two `.foo` different even if the linked-to symbols foo and bar
are defined in the same section. This is a deliberate choice so that we don't
need to know the section where foo and bar are defined beforehand.