Use scons target and dependency system instead of ad-hoc options.
Now is simply a matter of naming what to build. For example:
scons libgl-xlib
scons libgl-gdi
scons graw-progs
scons llvmpipe
and so on. And there is also the possibility of scepcified subdirs, e.g.
scons src/gallium/drivers
If nothing is specified then everything will be build.
There might be some rough corners over the next days. Please bare with me.
Now that draw depends on llvm it is very difficult to correctly handle
broken llvm installations. Either the user requests LLVM and it needs to
supply a working installation. Or it doesn't, and it gets no LLVM
accelerate pipe drivers.
Everybody is using the C99's integer types. Everybody except Microsoft,
which in turns means everybody is including their own definitions of C99
integer types for MSVC, causing duplicate definitions when linking two
projects. This is the case of building Gallium and LLVM with MSVC.
Shipping alternative stdint.h and stdbool.h headers for MSVC allows us
to share a single definition. It also removes clutter from the Gallium
headers.
