r300g: don't set sample positions to the pixel center if MSAA is disabled

but an MSAA resource is bound. This effectively makes the MSAA disable switch
not affect rasterization, but it still affects the alpha-to-one and
alpha-to-coverage states. This hardware just lacks a proper MSAA disable
switch.

This fixes graphics corruption in sauerbraten.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=59194
automake: Convert Gallium target and winsys
gallium: Add common automake include file

v2: Matt Turner <mattst88@gmail.com>
    Remove ARCH_FLAGS/OPT_FLAGS

v3: Johannes Obermayr <johannesobermayr@gmx.de>
    Add -I$(top_srcdir)/include to GALLIUM_CFLAGS
r300g: Use gallium automake include file

[mattst88] v2: Remove ARCH_FLAGS/OPT_FLAGS
r300g: Build a libtool archive
r300g: Link ralloc.c and register_allocate.c into separate library
radeon/winsys: Convert to automake
trace: Convert to automake
libgallium: Convert to automake
r600g: Use gallium automake include file
i915g: Convert to automake
i915/winsys/drm: Convert to automake
i915/winsys/sw: Convert to automake
rbug: Convert to automake
llvmpipe: Convert to automake
softpipe: Convert to automake
svga: Convert to automake
nouveau: Convert to automake
nv30: Convert to automake
nv50: Convert to automake