RFC: Add GNU_PROPERTY_1_NEEDED

[H.J. Lu]

Add GNU_PROPERTY_1_NEEDED:

 #define GNU_PROPERTY_1_NEEDED      GNU_PROPERTY_UINT32_OR_LO

to indicate the needed properties by the object file.

Add GNU_PROPERTY_1_NEEDED_SINGLE_GLOBAL_DEFINITION:

 #define GNU_PROPERTY_1_NEEDED_SINGLE_GLOBAL_DEFINITION  (1U << 0)

to indicate that the object file requires canonical function pointers and
cannot be used with copy relocation.

The PDF file is at

https://gitlab.com/x86-psABIs/Linux-ABI/-/wikis/uploads/9eca2f2defe62b0c5015bf2e3e8a9f05/Linux-gABI-1_needed-2021-06-18.pdf

-- 
H.J.