scons: Revamp how to specify targets to build.

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.

src/gallium/SConscript

@@ -1,30 +1,112 @@
-import os
+Import('env')
 
-Import('*')
+# 
+# Auxiliary modules
+#
 
 SConscript('auxiliary/SConscript')
 
-for driver in env['drivers']:
-	SConscript(os.path.join('drivers', driver, 'SConscript'))
+#
+# Drivers
+#
+
+SConscript([
+    'drivers/failover/SConscript', 
+    'drivers/galahad/SConscript',
+    'drivers/i915/SConscript', 
+    'drivers/i965/SConscript', 
+    'drivers/identity/SConscript', 
+    'drivers/llvmpipe/SConscript', 
+    'drivers/rbug/SConscript',
+    'drivers/r300/SConscript', 
+    'drivers/softpipe/SConscript',
+    'drivers/svga/SConscript', 
+    'drivers/trace/SConscript', 
+])
+
+if env['dri']:
+    # These drivers depend on drm headers
+    SConscript([
+        # XXX: nouveau drivers have a tight dependency on libdrm, so to enable
+        # we need some version logic before we enable them. Also, ATM there is
+        # no nouveau target in scons
+        #'drivers/nouveau/SConscript', 
+        #'drivers/nv50/SConscript', 
+        #'drivers/nvfx/SConscript',
+        'drivers/r600/SConscript', 
+    ])
+
+#
+# State trackers
+#
 
 # Needed by some state trackers
 SConscript('winsys/sw/null/SConscript')
 
 SConscript('state_trackers/python/SConscript')
-if platform != 'embedded':
+if env['platform'] != 'embedded':
 	SConscript('state_trackers/glx/xlib/SConscript')
 	SConscript('state_trackers/dri/SConscript')
 	SConscript('state_trackers/xorg/SConscript')
 	SConscript('state_trackers/egl/SConscript')
 	SConscript('state_trackers/vega/SConscript')
 
-if platform == 'windows':
+if env['platform'] == 'windows':
 	SConscript('state_trackers/wgl/SConscript')
 
+#
+# Winsys
+# 
+
 SConscript('winsys/SConscript')
 
-SConscript('targets/SConscript')
+#
+# Targets
+#
 
-if platform != 'embedded':
+SConscript([
+    'targets/graw-null/SConscript',
+])
+
+if env['x11']:
+    SConscript([
+        'targets/graw-xlib/SConscript',
+        'targets/libgl-xlib/SConscript',
+    ])
+
+if env['platform'] == 'windows':
+    SConscript([
+        'targets/libgl-gdi/SConscript',
+        #'egl-gdi/SConscript',
+    ])
+
+if env['dri']:
+    SConscript([
+        'targets/SConscript.dri',
+	    'targets/dri-i915/SConscript',
+	    'targets/dri-i965/SConscript',
+	    #'targets/dri-nouveau/SConscript',
+	    'targets/dri-r300/SConscript',
+        'targets/dri-r600/SConscript',
+	    'targets/dri-swrast/SConscript',
+	    'targets/dri-vmwgfx/SConscript',
+    ])
+
+if env['xorg']:
+    SConscript([
+        #'targets/xorg-i915/SConscript',
+        #'targets/xorg-i965/SConscript',
+        #'targets/xorg-nouveau/SConscript',
+        #'targets/xorg-radeon/SConscript',
+        'targets/xorg-vmwgfx/SConscript',
+    ])
+
+
+#
+# Unit tests & tools
+#
+
+if env['platform'] != 'embedded':
 	SConscript('tests/unit/SConscript')
 	SConscript('tests/graw/SConscript')
+