sanitize python env and subprocess i/o

emcc

@@ -11,6 +11,8 @@
 # To make modifications to this file, edit `tools/run_python_compiler.sh` and
 # then run `tools/create_entry_points.py`
 
+unset _PYTHON_SYSCONFIGDATA_NAME
+
 if [ -z "$PYTHON" ]; then
   PYTHON=$EMSDK_PYTHON
 fi
@@ -29,7 +31,7 @@ if [ -z "$PYTHON" ]; then
 fi
 
 if [ -z "$_EMCC_CCACHE" ]; then
-  exec "$PYTHON" "$0.py" "$@"
+  exec "$PYTHON" -E "$0.py" "$@"
 else
   unset _EMCC_CCACHE
   exec ccache "$0" "$@"

emconfigure

@@ -28,4 +28,4 @@ if [ -z "$PYTHON" ]; then
   exit 1
 fi
 
-exec "$PYTHON" "$0.py" "$@"
+exec "$PYTHON" -E "$0.py" "$@"

emmake

@@ -28,4 +28,4 @@ if [ -z "$PYTHON" ]; then
   exit 1
 fi
 
-exec "$PYTHON" "$0.py" "$@"
+exec "$PYTHON" -E "$0.py" "$@"

tools/shared.py

@@ -103,6 +103,7 @@ def run_process(cmd, check=True, input=None, *args, **kw):
   sys.stdout.flush()
   sys.stderr.flush()
   kw.setdefault('universal_newlines', True)
+  kw.setdefault('encoding', 'utf-8')
   ret = subprocess.run(cmd, check=check, input=input, *args, **kw)
   debug_text = '%sexecuted %s' % ('successfully ' if check else '', shlex_join(cmd))
   logger.debug(debug_text)