ELF Tool Chain Code

API dwarf_attrval_flag() should properly handle an attribute with
(DWARF4) form DW_FORM_flag_present which implicitly indicates the
presence of the attribute. Manual page is updated to reflect this
change.

Turn on SVN keyword expansion.

Ticket: #348

Add `$Id$` keywords.

Ticket: #348

Fix typos.

* No longer keep a list of DIE internally. DIE descriptor is now allocated by calls to dwarf_child(), dwarf_siblingof() and dwarf_offdie() and the application code needs to free it when no longer used.
* Implement deallocation type DW_DLA_DIE.
* Removed unused DIE hash tables.

Let dwarf_attrval_flag() return a determined (1 or 0) boolean value
like dwarf_formflag().

dwarf_attrval_unsigned() should be able to retrieve a DW_FORM_udata attr value.

DW_FORM_addr, DW_FORM_data1, DW_FORM_data2, W_FORM_data4 and W_FORM_data8
don't belong to the REFERENCE class and are invalid forms for attribute
DW_AT_abstract_origin.

* Function dwarf_attrval_signed() should also accept DW_FORM_data2,
DW_FORM_data4 and DW_FORM_data8.
* The value returned dwarf_attrval_signed() needs to be signed extended.

Consistently use Dwarf_Half to hold DWARF attribute constant.