There's a merged pull request on the void-packages repository

SuiteSparse: update to 7.6.0.
https://github.com/void-linux/void-packages/pull/48223

Description:
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#### Testing the changes
- I tested the changes in this PR: **briefly**

I built and checked `octave` and `python3-cvxopt` on top of this (#47887 would be nice to do this on CI as well).

While doing this I discovered building cvxopt is broken on i686, so I fixed it. It just happens that suitesparse moved header files in 7.4.0 to `/usr/include/suitesparse` and cvxopt figures this out for 64 bit but not for 32 bit). No need to rebuild cvxopt since our current binary is fine (it was last built with suitesparse 7.3.1).

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