[PATCH] Xbox PE subsystem support

["Myria" <asterisk at graces dot dricas dot com>]

This simple patch adds support for --subsystem:xbox to the ix86-pe emulation 
of ld.

The OpenXDK project ( http://www.openxdk.org/ ) is a project to make an 
open-source development kit for the Microsoft Xbox native OS.  Among the 
things needed, of course, is a compiler and linker.  Due to the similarities 
between Xbox and Win32, the PE build tools would work well, with few 
changes.

This patch adds --subsystem:xbox, value 14, officially and publicly defined 
as IMAGE_SUBSYSTEM_XBOX in Microsoft's winnt.h header file.  It is known 
that Microsoft's own Xbox Development Kit (XDK) compiles developers' games 
into standard PE format, with subsystem 14.  The resulting PE file is later 
converted to the PE-like "XBE" format.  We would like to continue with this 
tradition; in fact, the current OpenXDK does the same already.

In addition, this patch adds support for arbitrary subsystem numbers, 
like --subsystem=123.  This is for future use so hopefully others in 
unforeseen projects will not have to modify binutils to use a different 
subsystem.  When an arbitrary number is used that ld does not recognize, it 
assumes the entry point is mainCRTStartup.  If, however, the number is known 
by ld, as in the user typing --subsystem:2 ("windows"), the entry point will 
be set to the proper default.  The subsystem number is handled as a "0" base 
to strtoul, meaning it is decimal by default, and octal and hex can be used 
by prepending 0 or 0x.

Finally, "xbox" is recognized as a target, being equivalent to 
i686-pc-mingw32, whose settings are acceptable for OpenXDK.  This gives the 
rather convenient --target=xbox setting as well as executable names xbox-ld, 
xbox-as, etc.

Full list of changes:

- /config.sub now recognizes "xbox" as an alias for i686-pc-mingw32
- ld now recognizes --subsystem:xbox as 14 with mainCRTStartup
- ld now allows numeric subsystem numbers like --subsystem:1234
- ld manpage and texinfo updated to note new --subsystem usages
- removed weird #if in pe.em that selected between 2 identical fragments

I'm new to this patch thing and binutils so I probably made a mistake 
somewhere...  Also, some of you might not like this patch.  Any comments 
would be appreciated.  Thanks!

Melissa Mears

Attachment: binutils-xbox.patch
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