[Bug debug/61352] gcc 4.9.0 fails to execute dsymutil when linking executables on darwin

[dominiq at lps dot ens.fr]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61352

--- Comment #6 from Dominique d'Humieres <dominiq at lps dot ens.fr> ---
r208320 (2014-03-04) generates the *.dSYM folder, r208478 (2014-03-11) does
not.