Make dwarf_init_path_a error non-fatal

libdwarf failing to parse an object should not inhibit falling back to
parsing the ELF symtab.

Author: GHF

src/symbols/dwarf/dwarf_resolver.cpp

@@ -143,22 +143,30 @@ namespace libdwarf {
                 buffer = std::unique_ptr<char[]>(new char[CPPTRACE_MAX_PATH]);
             }
             dwarf_set_de_alloc_flag(0);
-            auto ret = wrap(
-                dwarf_init_path_a,
+            Dwarf_Error error = nullptr;
+            auto ret = dwarf_init_path_a(
                 object_path.c_str(),
                 buffer.get(),
                 CPPTRACE_MAX_PATH,
                 DW_GROUPNUMBER_ANY,
                 universal_number,
                 nullptr,
                 nullptr,
-                &dbg.get()
+                &dbg.get(),
+                &error
             );
             if(ret == DW_DLV_OK) {
                 ok = true;
             } else if(ret == DW_DLV_NO_ENTRY) {
                 // fail, no debug info
                 ok = false;
+            } else if(ret == DW_DLV_ERROR) {
+                // fail, parsing error
+                ok = false;
+                if(trace_dwarf) {
+                    auto msg = raii_wrap(dwarf_errmsg(error), [this, error] (char*) { dwarf_dealloc_error(dbg.get(), error); });
+                    std::fprintf(stderr, "dwarf error: %s\n", msg.get());
+                }
             } else {
                 ok = false;
                 PANIC("Unknown return code from dwarf_init_path");