size_report: Don't assume all paths start with ZEPHYR_BASE

Instead of crashing when a source file outside of ZEPHYR_BASE is
detected we accept it as-is to include it in the report.

This fixes #5866

Signed-off-by: Sebastian Bøe <[email protected]>

Author: SebastianBoe

scripts/footprint/size_report

@@ -35,7 +35,13 @@ def load_symbols_and_paths(bin_nm, elf_file, path_to_strip=""):
         symbol, path = parse_symbol_path_pair(line)
 
         if path:
-            processed_path = Path(path).relative_to(Path(path_to_strip))
+            p_path          = Path(path)
+            p_path_to_strip = Path(path_to_strip)
+            try:
+                processed_path = p_path.relative_to(p_path_to_strip)
+            except ValueError as e:
+                # path is valid, but is not prefixed by path_to_strip
+                processed_path = p_path
         else:
             processed_path = Path(":")