There is an updated pull request by fosslinux against master on the void-packages repository

https://github.com/fosslinux/void-packages python-matplotlib-fix
https://github.com/void-linux/void-packages/pull/24988

python-numpy: fix for armv5tel-musl.
in fenv.h, musl disables the normal set of constants that you would get
on arm with an arm device with an fpu (armv6 and up), but armv5tel on
void uses softfloat all the time. But python3-numpy dosen't use these to
interact with the fpu (the compiler would generate those instructions)
and rather just uses those constants for a generic GCC implementation.
So we give them out anyway.

python-numpy uses the same patch from python3-numpy.

A patch file from https://github.com/void-linux/void-packages/pull/24988.patch is attached