riscv: Make ELF flags RVE-aware

[Noxime]

This fixes the ELF header flags when targetting embedded RISC-V (rv32e and rv64e).

I think this is the only fix required for when LLVM merges D70401 and RVE targets can be added.

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[jackh726]

Agh not my area of expertise at all

r? compiler

[cjgillot]

Not mine either.
r? @bjorn3 or @nikic can you help?

[bjorn3]

Suggested change

	// Check if embedded is enabled
	// Specify if the embedded abi is used

It seems that the embedded abi can be used even in programs that use the full RV32I instruction set¹. This flag only determines if the embedded abi is used as I understand it², not if the object file is limited to RV32E instructions.

Footnotes

1. https://github.com/riscv-non-isa/riscv-eabi-spec/blob/master/EABI.adoc#1-goals ↩

2. https://github.com/riscv-non-isa/riscv-elf-psabi-doc/blob/master/riscv-elf.adoc#file-header ↩

[bors]

☔ The latest upstream changes (presumably #114332) made this pull request unmergeable. Please resolve the merge conflicts.

[Noxime]

Looks to be fixed in #114332