support for MSVC-style sub-section merging

[Joseph S. Myers]

On Mon, 12 Jul 2004, Jan Beulich wrote:

> Second try. It still had to become atarget macro, in order to be able to
> concatenate it with other string constants. Bootstrapped and tested on
> i686-pc-linux-gnu. Jan

It doesn't need concatenating, it could be included in the output strings
using %s in the printf formats, but I'll leave it to whoever reviews this
patch to decide what they think on the matter.

-- 
Joseph S. Myers               http://www.srcf.ucam.org/~jsm28/gcc/
    jsm@polyomino.org.uk (personal mail)
    jsm28@gcc.gnu.org (Bugzilla assignments and CCs)