If you mean "as their official compiler", the answer to both questions is "no"; they have, instead, Sun^WOracle Solaris Studio's compilers. If you mean "in their package system", they could offer both, but currently only appear to offer GCC 3 and GCC 4.5.

If you mean "as their official compiler", the answer to both questions is "no"; they have, instead, IBM XL C/C++.

If you mean "as their official compiler", the answer to both questions is "no"; they have, instead, HP C/aC++.

No, it makes it a combination of GPL'ed and non-GPL'ed code, which may make it "code that's in violation of one or the other license" or, alternatively, "code that's not entirely licensed in a fashion acceptable to the GCC developers".

If you're trying, you're probably doing it slowly and carefully enough that you don't hit the window border drag region. This happens (on occasion, not particularly often, but often enough to be a small irritation) when I'm doing a quick select-and-copy (or, when not on a Mac, a quick select-and-paste-current-selection).

Sorry I didn't notice the cursor image change in the few milliseconds between hitting the region where selecting grabs the border and clicking the trackpad.

In which desktop environments can I copy text from a terminal window without using a pointing device?

You can buy an infinite number of GCC licenses for the same price, unless you mean something other than "a right to use the software" by "license". Do you mean "a few GCC support contracts"?

I don't have a mouse, but presumably you meant "mouse or trackpad".

By having the pointer a slight bit to the left of the left-hand edge of the text in the window.

Wrong. The cursor changes from the text cursor (meaning it'll select text if you drag it) to the horizontal resize cursor (meaning it'll drag the border) before you hit the border.

No.

As OS X users finally get the power to unintentionally resize their terminal emulator windows when trying to select text that goes right up to the margin, just as other UN*X users have had for ages. :-)

(Yes, I've done that on a number of times on FreeBSD/Linux/Solaris/etc. inside $PICK_YOUR_TERMINAL_EMULATOR, but didn't feel the joy of doing that on OS X until Lion.)

Actually, with OS X, you can go below the system call layer (but not down to the device driver layer, as most of those are part of the non-open-source part of the kernel-mode code, and not down to some file systems such as AFP, as the AFP client isn't open-source either). The big problem would be with debugging stuff sufficiently far above the system call layer, such as problems in the Cocoa Framework and AppKit layers.

mavericks.local$ sw_vers
ProductName: Mac OS X
ProductVersion: 10.9
BuildVersion: 13A603
mavericks.local$ bash --version
GNU bash, version 3.2.51(1)-release (x86_64-apple-darwin13)
Copyright (C) 2007 Free Software Foundation, Inc.

And that version is GPLv2.

Well, I'm not sure more recent versions of OS X "include" a compiler in the sense that you have the compiler available on the machine as delivered, but, in Mavericks, if you try to run a developer command-line tool, it pops up a window asking if you want to install Xcode or just the command-line developer tools. As of the current version of Xcode (5), they have nothing using GCC's front end, just clang. Xcode 4.2 through 4.6.x included only llvm-gcc (GCC front end, LLVM back end) and clang.

As of Mountain Lion, no, although if, for example, you try to run xterm from the command line, it pops up a window telling you that you need to install X and offering to open up the Xquartz Web site to download and install it.

If you mean an advantage of not basing their GUI on X (it isn't, in fact, based on X; the X server runs on top of the native GUI), yes, that would be an advantage.

Presumably something other than a terminal emulator window (which is provided with Terminal.app). You can ssh in if you've enabled it, and, at least on some versions of OS X, you can log in at the login screen with a user name of ">console", at which point it shuts down the window system and puts you at a getty prompt on the system console. No virtual terminals, however.

Shells, plural - bash, tcsh, ksh (starting in, I think, Tiger), zsh. I think bash is the default; it might have been tcsh in earlier releases.

That was not true until Xcode 5.

What you got as "gcc", prior to Xcode 4.2, was GCC. What you got, from Xcode 4.2 to 4.6.3, was llvm-gcc, which had GCC's front end and an LLVM-based back end, so it wasn't fully the real GCC but it also didn't use clang as the front end and didn't give clang's error reporting. What you got, starting with GCC 5.0, was clang.

X: just like 10.8, you need XQuartz. At least it's not different from 10.8.

Command-line compiler tools: if, for example, you just type "gcc" at the command line just for the lulz, it'll pop up a window (so your command line had better be in a Terminal window on the machine on which you're running your shell) asking whether you want Full Frontal Xcode or just the command-line tools. If you select the latter, it'll plop them in an obscure directory under /Library but will plant stuff in /usr/bin that runs those commands. If you select the former, I suspect it'll plop them under /Applications/Xcode.app but will plant stuff in /usr/bin that runs those commands. (Having installed the command-line tools on my Mavericks VM, and then installed Xcode, I don't know what happens if you start by installing Xcode. I do know that if you do both, you get two count 'em two separate copies of, at minimum, the clang program.)

Signed applications, Java: not much, if anything, has changed there from 10.8.

Open source package manager: OS X doesn't come with one, so no change.

I really do not want an iPod, or even an iPad, that I have to shave.

Yes, it's meant to run on all sorts of lighter hardware.

Srsly, Linux is meant to run on whatever the hell can run Linux. That's it. Any other claim is bullshit.

Presumably you don't mean "Mac OS X is a desktop operating system, and the operating system in question is (based on) OpenBSD", given that the latter is not true. OS X is based on Mach 3, various flavors of BSD in the kernel and UNIX-layer userland, and a fair bit of Apple-devloped code in the kernel and UNIX-layer userland; most of the BSD in the kernel and UNIX-layer userland comes from FreeBSD and NetBSD, not OpenBSD.

The power management stuff is largely Apple-developed.

If you view modern Windows's NT core, dating back to the early '90's, as "an antiquated core with features continuously layered on", requiring "a rewrite from the ground up", then do you view, say, OS X's core, dating back at least to the late '90's, and back to the late '80's/early '90's if you go all the way back to NeXTStEP, as not being "an antiquated core with features continuously layered on" and not requiring "a rewrite from the ground up"? What about Linux (dating back to the early '90's, again) or the *BSDs (ditto)?