Fix PR456:\

Fix PR456:\
Tools and libraries will be built into $(BUILD_OBJ_ROOT)/$(BuildMode)/bin and \
$(BUILD_OBJ_ROOT)/$(BuildMode)/lib, respectively. Furthermore, the example \
programs will go in $(BUILD_OBJ_ROOT)/$(BuildMode)/examples to keep them \
separate from the tools and hopefully out of the PATH. Install targets \
have not changed.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@17953 91177308-0d34-0410-b5e6-96231b3b80d8