tools: Update asm-differ and add support for -mw (make, watch)

tools/diff_settings.py

@@ -1,4 +1,5 @@
-#!/usr/bin/env python3
+from pathlib import Path
+
 
 def apply(config, args):
     config['arch'] = 'aarch64'
@@ -6,3 +7,16 @@ def apply(config, args):
     config['myimg'] = 'build/uking'
     config['source_directories'] = ['src']
     config['objdump_executable'] = 'tools/aarch64-none-elf-objdump'
+
+    for dir in ('build', 'build/nx64-release'):
+        if (Path(dir) / 'build.ninja').is_file():
+            config['make_command'] = ['ninja', '-C', dir]
+
+
+def map_build_target(make_target: str):
+    if make_target == "build/uking":
+        return "uking"
+
+    # TODO: When support for directly diffing object files is added, this needs to strip
+    # the build/ prefix from the object file targets.
+    return make_target