[RFC/Patch] : Enable Dwarf2 unwind on cygwin and mingw32

[Andrew Haley]

Danny Smith writes:
 > Danny Smith wrote:
 > 
 > 2004-11-25  Danny Smith  <dannysmith@users.sourceforge.net>
 > 
 >         * config.gcc (*-cygwin*): Add crtbegin.o, crtend.o as
 >         extra_parts.
 >         * config.gcc (*-mingw*): Likewise.
 >         * config/i386/cygming.h (DWARF2_UNWIND_INFO): Don't ovveride
 >         default.
 >         * config/i386/cygwin.h (STARTFILE_SPEC): Add crtbegin.o.
 >         (ENDFILE_SPEC): Define as crtend.o.
 >         * config/i386/mingw32.h (STARTFILE_SEC): Add crtbegin.o.
 >         (ENDFILE_SPEC): Define as crtend.o.
 >         * config/i386/t-cygming: Add rules for crtbegin.o, crtend.o.
 >         * config/i386/cygming-crtbegin.c: New file.
 >         * config/i386/cygming-crtend.c: New file.
 > 

We desperately need this for gcj, because we are being held back by
having to supprt sjlj.  But without being able to unwind through
callbacks, which I assume you still can't, this won't be useful.

Andrew.