illumos gate

http://smartos.org/bugview/OS-7733

While inspecting CTF diffs for GCC7, I noticed this in dockerexec:

f905ddb5-9113-c52a-d3ce-d0db83321d72:dockerinit $ ctfdump -c ./build/dockerexec | grep custr_alloc\(
extern void custr_alloc(void);

What's happening here is this DWARF:

<1><1f12>: Abbrev Number: 80 (DW_TAG_subprogram)
    <1f13>   DW_AT_external    : 1
    <1f14>   DW_AT_declaration : 1
    <1f15>   DW_AT_MIPS_linkage_name: (indirect string, offset: 0x600): custr_alloc
    <1f19>   DW_AT_name        : (indirect string, offset: 0x600): custr_alloc
    <1f1d>   DW_AT_decl_file   : 28
    <1f1e>   DW_AT_decl_line   : 35
 <1><1f1f>: Abbrev Number: 80 (DW_TAG_subprogram)

Note the lack of any formal parameter children. GCC4 doesn't generate these. But they don't seem useful at all.

So for dockerexec, we end up generating an argument-less entry. Later, when we see the real custr_alloc(), we do parse it fine, but we end up keeping the wrong version.

The fix is most likely to ignore these DW_AT_declaration entries.