swpipe: Make softpipe optional

* If we're using llvmpipe, don't reference
  softpipe. Reduce bloat.

src/add-ons/opengl/swpipe/GalliumContext.cpp

@@ -26,9 +26,10 @@ extern "C" {
 #include "state_tracker/st_gl_api.h"
 #include "state_tracker/st_manager.h"
 #include "state_tracker/sw_winsys.h"
-#include "softpipe/sp_public.h"
 #ifdef HAVE_LLVM
 #include "llvmpipe/lp_public.h"
+#else
+#include "softpipe/sp_public.h"
 #endif
 }
 
@@ -212,11 +213,10 @@ GalliumContext::CreateScreen()
 
 	#ifdef HAVE_LLVM
 	fScreen = llvmpipe_create_screen(winsys);
+	#else
+	fScreen = softpipe_create_screen(winsys);
 	#endif
 
-	if (fScreen == NULL)
-		fScreen = softpipe_create_screen(winsys);
-
 	if (fScreen == NULL) {
 		ERROR("%s: Couldn't create screen!\n", __FUNCTION__);
 		FREE(winsys);

src/add-ons/opengl/swpipe/Jamfile

@@ -24,7 +24,7 @@ if $(HAIKU_LLVM_DIR) {
 	SubDirSysHdrs /boot/common/include ;
 	HAIKU_LLVM_DIR = /boot/common/lib ;
 
-	HAIKU_SWPIPE_DRIVER +=
+	HAIKU_SWPIPE_DRIVER =
 		$(HAIKU_MESA_DIR)/lib.haiku/libllvmpipe.a ;
 
 	llvmLibraries =