Here's the latest proposed layout. It may need some fine tuning at some point, but I think it's a pretty good starting point.
-Brian
Mesa/
docs/ - documentation
include/
GL/ - OpenGL public headers
gl.h
glext.h
glx.h
glxext.h
glu.h
...
src/
glu/
sgi/ - SGI GLU code (C++)
mesa/ - old Mesa GLU code (C)
mini/ - subset GLU for embedded
glut/
glx/ - GLUT based on GLX
beos/ - GLUT for BeOS
dos/ - GLUT for DOS
ggi/ - GLUT for GGI
mini/ - subset/embedded glut
widgets/ - SGI widget code
mesa/
glapi/
glapi*.[ch] - dispatcher files
APIspec file
gl*.py - Python API scripts
main/ - core Mesa sources
attrib.c
context.c
enable.c
...
CPU detection code
transform/ - was tnl
t_*.[ch]
X86/3Dnow code
math/ - math/vector routines
m_*.[ch]
swrast/ - s/w rasterization
s_*.[ch]
mmx_blend.S
swsetup/ - was swrast_setup
ss_*.[ch]
arraycache/ - vertex array stuff
ac_*.[ch]
drivers/
common/ - reusable driver code
and transform_dd/ files
x11/ - X11 (XMesa) driver
osmesa/ - OSMesa driver
swfbdev/ - software fbdev driver
radeon/ - DRI/fbdev driver
radeon-es/ - subset radeon fbdev driver
r200/ ...
mga/ - DRI/fbdev driver
windows/
beos/
ggi/
glide/ - was FX driver
dos/
dri/ - es dri code
kernel/ - kernel drivers, modules
drm/
shared/
linux/
bsd/
fbdev/
radeonfb/
radeonfb-2.5/
agpgart/
miniglx/ - MiniGLX libGL.so
glx/ - XF86/DRI libGL (someday?)
progs/
xdemos/ - Xlib / GLX demos
demos/ - existing Mesa demos
redbook/ - OpenGL redbook programs
samples/ - SGI sample progs
test/ - tests, omitted from tarball
images/ - sample images for demos
BeOS/ - old BeOS demos
ggi/ - GGI progs
windml/ - WindML progs
util/ - utility functions, etc.
lib/ - compiled libraries
bin/ - shell scripts, etc.
