libpng.a(pngerror.o): requires dynamic R_X86_64_PC32 reloc against 'stderr'

I'm on Ubuntu 20 focal and I am trying to build Blender as a Python module. The final step of the build instructions is where I am having problems.

My building gets to 100%, but then fails with the following output:

/usr/bin/ld.gold: error: /usr/lib/x86_64-linux-gnu/libpng.a(pngerror.o): requires dynamic R_X86_64_PC32 reloc against 'stderr' which may overflow at runtime; recompile with -fPIC

I have tried sudo make bpy -fPIC, but this throws another error:

make: pic: No such file or directory
make: *** No rule to make target 'pic'. Stop.

I assume the -fPIC error is because I'm stupid, and I am supposed to compile libpng with fpic support (or something like that), rather than tack it on to the end of the above command, but I don't know really...

I've searched for a while now, and the closest answer I've come to is this one, which says to download and compule libpng and then to do something with libpng.a (what exactly, I've no idea).

How can I fix this issue?