App.__find_dir() Support --topdir-format make:XXX

The global --topdir-format make:XXX option to jw-pkg is half-baked at best, and __find_dir() ignores it entirely. Make __find_dir() return some Makefile-syntax-formatted output if the option is present. Not used anywhere, currently, and, hence, badly tested, but still better than the situation before.
Signed-off-by: Jan Lindemann <jan@janware.com>

src/python/jw/pkg/App.py

@@ -130,7 +130,17 @@ class App(Base):
         pretty: bool = True,
     ) -> str | None:
 
-        def format_pd(name: str, pd: str, pretty: bool):
+        def __format_relpath(path: str):
+            if path.startswith('./'):
+                return path[2:]
+            if path.endswith('/.'):
+                return path[:-2]
+            return path
+
+        def __relpath(target: str, base: str):
+            return __format_relpath(os.path.relpath(target, base))
+
+        def __format_pd(name: str, pd: str, pretty: bool):
             if not pretty:
                 return pd
             if self.__topdir_fmt == 'absolute':
@@ -138,7 +148,11 @@ class App(Base):
             if self.__topdir_fmt == 'unaltered':
                 return pd
             if self.__topdir_fmt == 'relative':
-                return os.path.relpath(pd, self.__pretty_topdir)
+                return __relpath(pd, self.__topdir)
+            if self.__topdir_fmt.startswith('make:'):
+                relpath = __relpath(pd, self.__topdir)
+                var = self.__topdir_fmt.split(':')[1]
+                return __format_relpath(f'$({var})/{relpath}')
             if name == self.__top_name:
                 return self.__pretty_topdir
             raise NotImplementedError(
@@ -149,11 +163,11 @@ class App(Base):
         if pd is None:
             return None
         if not search_subdirs and not search_absdirs:
-            return format_pd(name, pd, pretty)
+            return __format_pd(name, pd, pretty)
         for sd in search_subdirs:
             path = pd + '/' + sd
             if os.path.isdir(path):
-                ret = format_pd(name, pd, pretty)
+                ret = __format_pd(name, pd, pretty)
                 if sd and sd[0] != '/':
                     if ret == '.':
                         ret = ''