AndrewAPrice wrote:
Is my build system legally allowed to pull the GPL'ed source code from the original website, apply some patches, link it to my Apache licensed libraries, and build a binary?
Obviously yes, because so far you have not said anything about passing it on. So long as you do not redistribute the product, you can do whatever you want.
If you do redistribute the product, the GPL requires you to do so under its terms, or else the original copying of the code to you was invalid. In practice here this means you do need to publish the patches (at least to all recipients of the software, if not the general public). It is an open question whether you need to publish the build system, but as long as one can build a binary from the code you publish, that ought to be good enough.
AndrewAPrice wrote:
I'd like to distribute a bootable image of my OS and some accompanying software ported to my OS. Can I distribute this bootlable image containing only the binaries of my OS + accompanying software of which some is GPL'ed?
Yes, so long as the documentation of the OS (and that can be a booklet you distribute alongside the OS, or text files in the image) contain a copy of the GPL and a notice what software it applies to. You will need to make the source code available to all recipients of the OS image on request.
AndrewAPrice wrote:
Am I allowed to distribute GPL software (written by others) in binary format with my OS?
Yes, that is explicitly allowed in the license.
AndrewAPrice wrote:
Is it reasonable enough that the launching interface in my OS could have a description area that says "This software is licensed under the GNU General Public Licence and the source code and full license is avaliable at <website>. Code changes required to port it to my OS are avaliable at <website>."?
Yes, that would work. The harder part is going to be to ensure that the website stays up.