[ELF commit] Add new zstd compression algorithm

[Fangrui Song]

On 2022-08-02, Cary Coutant via Binutils wrote:
>In the gABI group, we have approved the addition of a new compression
>type, using the zstd library (zstandard.org). I'm about to commit this
>patch to add the new value to <elf/common.h>.
>
>https://groups.google.com/g/generic-abi/c/satyPkuMisk/m/dP2pPh9mAwAJ
>
>-cary
>
>
>include/elf/
>        * common.h: Add ELFCOMPRESS_ZSTD.
>
>
>diff --git a/include/elf/common.h b/include/elf/common.h
>index e4bc53e35b4..ebcd8f9e82c 100644
>--- a/include/elf/common.h
>+++ b/include/elf/common.h
>@@ -588,6 +588,8 @@
>
> /* Compression types.  */
> #define ELFCOMPRESS_ZLIB   1           /* Compressed with zlib.  */
>+#define ELFCOMPRESS_ZSTD   2           /* Compressed with zstd  */
>+                                       /* (see http://www.zstandard.org). */
> #define ELFCOMPRESS_LOOS   0x60000000  /* OS-specific semantics, lo */
> #define ELFCOMPRESS_HIOS   0x6FFFFFFF  /* OS-specific semantics, hi */
> #define ELFCOMPRESS_LOPROC 0x70000000  /* Processor-specific semantics, lo */

Thanks:)

Interested folks may help
https://sourceware.org/bugzilla/show_bug.cgi?id=29397 ("binutils: support zstd for SHF_COMPRESSED debug sections")

The build system change is probably the most difficult one ;-)