[RFC] Cleaning up die() error messages

Hello git list,

I've started working on cleaning up the various die() error messages found throughout git, and had a few thoughts along the way.

Currently, I've been adding missing program name prefixes, and quoting path names (e.g., "%s" -> "'%s'"), but before I go any further, I'm wondering if this is a) desired, or perhaps b) superfluous? This may be best discussed with along-side the patch - which'll follow shortly. ;)

Also, I got to thinking whether it might be an idea to use the following idiom in the code:

	[shell scripts]
	prog="`basename $0`"
	..
	foo || die "${prog}: foo failed"

	[C sources]
	static char *prog;
	..
	static inline void set_prog_name (char *argv0)
	{
		prog = strrchr(argv0, '/');
		if (prog)
			prog++;
		else
			prog = argv0;
	}
	..
	int main (int argc, char **argv)
	{
		set_prog_name(argv[0]);
		..
		if (!do_bar())
			die("%s: do_bar() failed", prog);
		..
	}

The idea behind this being that, if any of the git programs get renamed (again :) there won't be a need for s/git-foo/git-bar/g just to fix-up die() error messages, and it'll also shave a *bit* off of the size of the compiled binaries. ;)

(Of course, the C parts (`prog' and `set_prog_name()') would go into a header, and not in every single C source file. ;)

So, any thoughts/comments/flames? :)

Best, Elfyn