* Add hooks HandleSectionStart() and HandleSectionEnd(). They are
invoked to bracket package file section, so the handler can
discriminate which section the attributes belong to.
HandleSectionStart() features a return parameter _handleSection, which
allows to handler to pick which sections it wants to handle.
* "package dump" does now print the section names.
If a FD is specified, instead of using the file with the given the FD is
used. Allows for adding entries without first copying them into the
directory structure.
This makes opening symlinks work universally in the build system tools.
Two mechanisms have been implemented, both of which don't always work.
The first is remapping via preprocessor macros. This fails where equally
named methods are used (e.g. STL fstream::open()). The other is using
hidden functions in the new libroot_build_function_remapper.a that is
linked into everything that is linked against libroot_build.so. This one
fails for functions that are defined inline in headers (Linux/glibc does
that). Together they seem to cover our build system needs ATM.
In HandleEntry() create the file/directory with sufficient permissions
for the user and set the archived permissions in HandleEntryDone(). This
makes sure child attributes and entries can be created.
* Match the attribute in a loop, use an attribute ID switch, do the
"seen" checks without the switch.
* Explicitly handle the case when encountering an unknown attribute.
* Use braces instead of brackets for lists.
* Semicolons and newlines separate items now. Remove handling for comma.
* Allow '\'' as quotation character.
* Remove assignment after variable name.
This should make the .PackageInfo format driver settings compatible, but
not vice versa. It is still stricter.
To avoid a clash with the regular version or an extra attribute level we
use the "package:provides.compatible" package attribute instead of
"package:version.major".
