[Bug libfortran/54736] GFORTRAN_CONVERT_UNIT causes malloc error on several platforms

[shart6 at utk dot edu]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54736

--- Comment #3 from Shane Hart <shart6 at utk dot edu> 2012-09-30 19:12:48 UTC ---
The patch does get rid of memory corruption.  However, there seem to be some
problems with search_unit returning true if an exception is found when there is
only one exception.

If n_elist = 1, then high = low = 0, and the funtion will always return 0, even
if the unit passed in to search for is in the exception list.