This libbacktrace patch corrects the amount of memory allocated when looking for the Mach-O dsym file. We weren't allocating space for the backslash. Thanks to Alex Crichton for noticing this. This also fixes the amount of space released when freeing diralc in the same function. Thanks to Francois-Xavier Coudert for noticing that. Bootstrapped and ran libbacktrace tests on x86_64-pc-linux-gnu. Committed to mainline.
Ian * macho.c (macho_add_dsym): Make space for '/' in dsym. Use correct length when freeing diralc.
