This resolves build error with Py3.9x, use meson build system
since autoconf/automake are no longer supported.
This adds ninja & meson as dependencies for Linux.
Needed to run mesa utilities with Python 3.9, see: https://cgit.freedesktop.org/mesa/mesa/commit/?id=6a841dbf4e4f0cb33bc36a8ba880a9bd6f6e7941
Edit: since running into this error on my first build, I'm no longer able to reproduce the Python failure, although Mesa-18.3.1 still contains the Python calls which are unsupported.
Now I'm running into a different linking error (below) which is resolved by updating to 20.3.4,
either way updating to a newer mesa allows make deps to build for me.
/usr/bin/ld: ../../../../src/gallium/auxiliary/.libs/libgallium.a(u_debug_symbol.o):(.bss+0x0): multiple definition of `symbols_hash'; ../../../../src/gallium/auxiliary/.libs/libgallium.a(u_debug_stack.o):(.bss+0x0): first defined here