[S] Change in coreboot[master]: util/crossgcc/buildgcc: Allow building CMake with multiple threads

[Michael Niewöhner (Code Review)]

Attention is currently required from: Felix Singer, Nico Huber, Martin L Roth, Elyes Haouas.

Michael Niewöhner has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/74156 )

Change subject: util/crossgcc/buildgcc: Allow building CMake with multiple threads
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Patch Set 1:

(1 comment)

Commit Message:

https://review.coreboot.org/c/coreboot/+/74156/comment/a3e650f9_ac04faf2 
PS1, Line 7: Allow building CMake with multiple threads
> I have tested this before uploading the patch.  --parallel  also seems to configure the threads which are used during the compilation. With  --parallel=1  only one thread was used, while  --parallel=32  made it using 32 threads.
>
> If there is a configure flag for it, I rather want to use that instead of  make -j . Though, I have to say I didn't check what the flag does :)

Well, I have tested it as well and my results strongly disagree ;)

The help text disagrees as well:
`--parallel=n            bootstrap cmake in parallel, where n is `

`--parallel` sets `cmake_parallel_make` which is only used during bootstrap (configure), not during the actual build, where `-j` is the right thing.