fbt/ufbt: Ensure POSIX paths are passed to GDB on all platforms (#3360)

* fbt/ufbt: Ensure POSIX paths are passed to GDB on all platforms
  GDB heavily dislikes forward slashes from Windows paths and strips
  them internally instead of normalizing them. Account for this by
  passing POSIX paths explicitly.
* fbt: different approach for posix path handling
* fbt, ufbt: further fixes for path handling
* fbt: explicit path stringification
* linter fixes

Co-authored-by: hedger <hedger@users.noreply.github.com>
Co-authored-by: hedger <hedger@nanode.su>
Co-authored-by: あく <alleteam@gmail.com>

scripts/fbt_tools/fbt_sdk.py

@@ -6,7 +6,7 @@ import shutil
 
 from fbt.sdk.cache import SdkCache
 from fbt.sdk.collector import SdkCollector
-from fbt.util import path_as_posix
+from fbt.util import PosixPathWrapper
 from SCons.Action import Action
 from SCons.Builder import Builder
 from SCons.Errors import UserError
@@ -80,7 +80,7 @@ class SdkMeta:
             vars,
             target=Entry(self.MAP_FILE_SUBST),
         )
-        return path_as_posix(expanded_vars)
+        return PosixPathWrapper.fixup_separators(expanded_vars)
 
 
 class SdkTreeBuilder:
@@ -149,7 +149,7 @@ class SdkTreeBuilder:
         meta.save_to(self.target[0].path)
 
     def build_sdk_file_path(self, orig_path: str) -> str:
-        return path_as_posix(
+        return PosixPathWrapper.fix_path(
             posixpath.normpath(
                 posixpath.join(
                     self.SDK_DIR_SUBST,