Escape backslashes

Author: tannewt

ports/zephyr-cp/cptools/cpbuild.py

@@ -150,7 +150,8 @@ async def run_command(
 
         # When on windows, use a responsefile if the command string is >= 8192
         if os.name == "nt" and len(command_string) >= 8192:
-            responsefile_contents = "\n".join(command[1:])
+            # Escape backslashes
+            responsefile_contents = "\n".join(part.replace("\\", "\\\\") for part in command[1:])
             responsefile.write_text(responsefile_contents)
             command_string = f"{command[0]} -v @{responsefile}"
     else: