[PATCH 2/2] libc-abis: Define ABSOLUTE ABI [BZ #19818][BZ #23307]

[Florian Weimer]

* Maciej W. Rozycki:

> Define a new ABSOLUTE ABI for static linker's use with EI_ABIVERSION 
> where correct absolute (SHN_ABS) symbol run-time load semantics is 
> required.  This way it can be ensured at static link time that a program 
> or DSO will not suffer from previous semantics where absolute symbols 
> were relocated by the base address, or symbols whose `st_value' is zero 
> silently ignored leading to a confusing "undefined symbol" error message 
> at load time, and instead "ELF file ABI version invalid" is printed with 
> old dynamic loaders, making it clear that there is an ABI version 
> incompatibility.

Is this really necessary?  It essentially precludes backporting the
fixes.