I think this is a known issue: DMD expects real.stringof to return a string in the %g format. However the GCC function used for formatting real numbers always returns the %e format.
There is a failing test for this in the test suite. (runnable/test42.d (test49)). Would it be OK to disable this test if a file a bug report on our bugtracker and on the gcc bugtracker? This would allow running the other tests in that file.
