Clean up libelf handling.

SConstruct:
    Clean up libelf handling.  Required better handling of
    per-build-root stuff in general (though libelf is the
    only thing in that category currently).
src/SConscript:
    No libelf-specific stuff in here anymore.
src/base/loader/elf_object.cc:
    Just need to include gelf.h... it includes libelf.h.

--HG--
extra : convert_revision : 3d6bdcf8233bda0ac8d08ff777de323df8aa45ae

src/SConscript

@@ -326,10 +326,6 @@ env.Command(Split('base/traceflags.hh base/traceflags.cc'),
             'base/traceflags.py',
             'python $SOURCE $TARGET.base')
 
-# libelf build is described in its own SConscript file.
-# SConscript-local is the per-config build, which just copies some
-# header files into a place where they can be found.
-SConscript('libelf/SConscript-local', exports = 'env', duplicate=0)
 SConscript('python/SConscript', exports = ['env'], duplicate=0)
 
 # This function adds the specified sources to the given build
@@ -358,7 +354,6 @@ def make_objs(sources, env):
 # the corresponding build directory to pick up generated include
 # files.
 env.Append(CPPPATH='.')
-env.Append(CPPPATH='./libelf')
 
 # Debug binary
 debugEnv = env.Copy(OBJSUFFIX='.do')