scons: fix build failed caused by Non-ASCII directory path

This patch addresses the issue of gem5 failing to build when
the build directory path contains non-ASCII characters.
The previous patches[1] that attempted to fix this issue
became ineffective after the upgrade of Python and pybind11
to new versions. This new patch manually sets the locale in
marshal.py based on the `LC_CTYPE` environment variable,
providing a comprehensive solution that works with Non-ASCII
build directory paths.

[1] https://gem5-review.googlesource.com/c/public/gem5/+/58369

Change-Id: I3ad28b6ee52fd347d2fe71f279baab629e88d12c
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/70818
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Bobby Bruce <bbruce@ucdavis.edu>
Maintainer: Bobby Bruce <bbruce@ucdavis.edu>

build_tools/marshal.py

@@ -48,6 +48,7 @@ interpretters, and so the exact same interpretter should be used both to run
 this script, and to read in and execute the marshalled code later.
 """
 
+import locale
 import marshal
 import sys
 import zlib
@@ -65,6 +66,11 @@ if len(sys.argv) < 4:
     print(f"Usage: {sys.argv[0]} CPP PY MODPATH ABSPATH", file=sys.stderr)
     sys.exit(1)
 
+# Set the Python's locale settings manually based on the `LC_CTYPE`
+# environment variable
+if "LC_CTYPE" in os.environ:
+    locale.setlocale(locale.LC_CTYPE, os.environ["LC_CTYPE"])
+
 _, cpp, python, modpath, abspath = sys.argv
 
 with open(python, "r") as f:

site_scons/gem5_scons/defaults.py

@@ -66,6 +66,7 @@ def EnvDefaults(env):
             "GEM5PY_LINKFLAGS_EXTRA",
             "LINKFLAGS_EXTRA",
             "LANG",
+            "LC_CTYPE",
         ]
     )