... don't have time to look at it at the moment:
#0 0x00007fcbb1ceb3b9 in wtap_open_offline (filename=<optimized out>, type=type@entry=0, err=err@entry=0x7fffd367cf8c, err_info=err_info@entry=0x7fffd367cfa8, do_random=do_random@entry=0)
at file_access.c:890
890 for (i = heuristic_open_routine_idx; i < open_info_arr->len; i++) {
Missing separate debuginfos, use: debuginfo-install glib2-2.38.2-2.fc20.x86_64 glibc-2.18-12.fc20.x86_64 libgcrypt-1.5.3-2.fc20.x86_64 libgpg-error-1.12-1.fc20.x86_64 zlib-1.2.8-3.fc20.x86_64
(gdb) bt
#0 0x00007fcbb1ceb3b9 in wtap_open_offline (filename=<optimized out>, type=type@entry=0, err=err@entry=0x7fffd367cf8c, err_info=err_info@entry=0x7fffd367cfa8, do_random=do_random@entry=0)
at file_access.c:890
#1 0x00007fcbb1cf51d4 in merge_open_in_files (in_file_count=in_file_count@entry=10, in_file_names=<optimized out>, in_files=in_files@entry=0x7fffd367cfa0, err=err@entry=0x7fffd367cf8c,
err_info=err_info@entry=0x7fffd367cfa8, err_fileno=err_fileno@entry=0x7fffd367cf9c) at merge.c:63
#2 0x000000000040186c in main (argc=<optimized out>, argv=0x7fffd367d198) at mergecap.c:317
(this was from a run like "mergecap -w mergecap.pcapng *")