Process files with missing DW_AT_name

With current behavior while scanning compile units the utility exits with
error if a unit does not contains an entry with name. However, some
packages, like arm-trusted-firmware, has entries without names. Since these
entries do not provide useful information for the mapping between binaries
to sources just skip them.

infrastructure/apertis-issues#81



Signed-off-by: Walter Lozano <walter.lozano@collabora.com>

src/main.rs

@@ -82,9 +82,12 @@ fn list_entries<R: Reader>(
                 .transpose()?
                 .ok_or_else(|| anyhow!("Missing DW_AT_comp_dir"))?;
 
-            let at_name = entry
-                .attr(gimli::DW_AT_name)?
-                .ok_or_else(|| anyhow!("Missing DW_AT_name"))?;
+            let at_name = if let Some(it) = entry.attr(gimli::DW_AT_name)? {
+                it
+            } else {
+                eprintln!("Warning: unit without name, skipping it");
+                continue;
+            };
 
             if let Some(r) = at_name.string_value(debug_str) {
                 let comp_name = r.to_string()?;