Synthetic symbol leak in elf_read_minimal_symbols

Synthetic symbol leak in elf_read_minimal_symbols

Detected this leak with valgrind memcheck:

==30840== 194 bytes in 1 blocks are definitely lost in loss record 9,138 of 10,922
==30840==    at 0x4C2DB8F: malloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==30840==    by 0x80DF82: bfd_malloc (libbfd.c:193)
==30840==    by 0x80E12D: bfd_zmalloc (libbfd.c:278)
==30840==    by 0x819E80: elf_x86_64_get_synthetic_symtab (elf64-x86-64.c:6835)
==30840==    by 0x4F7B01: elf_read_minimal_symbols(objfile*, int, elfinfo const*) (elfread.c:1124)
==30840==    by 0x4F7CE7: elf_symfile_read(objfile*, enum_flags<symfile_add_flag>) (elfread.c:1182)
==30840==    by 0x7557FC: read_symbols(objfile*, enum_flags<symfile_add_flag>) (symfile.c:861)
==30840==    by 0x755EE1: syms_from_objfile_1(objfile*, section_addr_info*, enum_flags<symfile_add_flag>) (symfile.c:1062)

We perform a dynamic allocation in
elf64-x86-64.c:elf_x86_64_get_synthetic_symtab

  s = *ret = (asymbol *) bfd_zmalloc (size);

that appear to never get freed.

gdb:

2017-08-17  Alex Lindsay  <alexlindsay239@gmail.com>

	* elfread.c (elf_read_minimal_symbols): xfree synthsyms.