Bug 23708 - categorize void* to pointer change as harmless

Bug 23708 - categorize void* to pointer change as harmless

Changing a void* pointer into another pointer of the same size is a
change that is harmless in terms of data layout.

This commit thus categorizes such a change as harmless.

	* include/abg-comparison.h (VOID_PTR_TO_PTR_CHANGE_CATEGORY): New
	enumerator in the diff_category enum.  Also, adjust the
	EVERYTHING_CATEGORY enumerator.
	* include/abg-fwd.h (is_void_pointer_type): Declare new function.
	* src/abg-comp-filter.cc (has_void_ptr_to_ptr_change): Define new
	static function and ...
	(categorize_harmless_diff_node): ... use it here.
	* src/abg-comparison.cc (get_default_harmless_categories_bitmap):
	Add the new abigail::comparison::VOID_PTR_TO_PTR_CHANGE_CATEGORY
	category in here.
	(operator<<(ostream& o, diff_category c)): Add support for the new
	VOID_PTR_TO_PTR_CHANGE_CATEGORY.
	* src/abg-ir.cc	(is_void_pointer_type): Define new function.
	* tests/data/Makefile.am: Add the new test material below to source distribution.
	* tests/data/test-diff-filter/test47-filter-void-ptr-change-report-0.txt:
	New test reference output.
	* tests/data/test-diff-filter/test47-filter-void-ptr-change-v{0,1}.c:
	Source code of the new binary test input below.
	* tests/data/test-diff-filter/test47-filter-void-ptr-change-v{0,1}.o:
	New binary test input.
	* tests/test-diff-filter.cc: Add the test input/output above to
	test harness.

Signed-off-by: Dodji Seketeli <dodji@redhat.com>