There's a closed pull request on the void-packages repository python-numpy: fix for armv5tel-musl. https://github.com/void-linux/void-packages/pull/24988 Description: 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.