New review comment by classabbyamp on void-packages repository

https://github.com/void-linux/void-packages/pull/48354#discussion_r1473092843

Comment:
```suggestion
	local _vendor_spirv="../thirdparty/SPIRV-Headers/include/spirv/unified1"
	local _system_spirv="${XBPS_CROSS_BASE}/usr/include/spirv/unified1"
	vsed -i src/meson.build -e "s|${_vendor_spirv}|${_system_spirv}|"
```
but this could also be done without variables. it's fine if it's a long line in this case