environment: copy self.cmd_line_options to not modify original options
That dict gets modified when adding default_options, but mesonmain will
need to keep the original values.
@@ -288,7 +288,7 @@ class Environment:
self.cross_info = CrossBuildInfo(self.coredata.cross_file)
else:
self.cross_info = None
- self.cmd_line_options = options.cmd_line_options
+ self.cmd_line_options = options.cmd_line_options.copy()
# List of potential compilers.
if mesonlib.is_windows():
