[Bug debug/46749] gcc.dg/debug/pr41893-1.c -gdwarf-2 testsuite failures on darwin

[iains at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46749

--- Comment #15 from Iain Sandoe <iains at gcc dot gnu.org> 2010-12-01 21:34:19 UTC ---
splitting the command into compile and link steps will intentionally remove the
dsymutil step -  thus making the problem 'go away' ...

dsymutil should _only_ be called if there is a source file on the c/l 
(which would have its object deleted and thus be unavailable for debug).