https://bugs.gentoo.org/902463

https://github.com/dxx-rebirth/dxx-rebirth/pull/705
https://github.com/dxx-rebirth/dxx-rebirth/commit/189ac23f61605903eb3eaa0004d287b7bd9296bc
--- a/SConstruct
+++ b/SConstruct
@@ -324,3 +324,3 @@
 		def __init__(self,env,keyviews,_l=[]):
-			self.flags = {k: env.get(k, _l)[:] for k in itertools.chain.from_iterable(keyviews)}
+			self.flags = {k: env.get(k, _l).copy() for k in itertools.chain.from_iterable(keyviews)}
 		def restore(self,env):
@@ -1493,3 +1493,3 @@
 			user_settings.max_axes_per_joystick = user_settings.max_buttons_per_joystick = user_settings.max_hats_per_joystick = 0
-		successflags['CPPDEFINES'] = CPPDEFINES = successflags.get('CPPDEFINES', [])[:]
+		successflags['CPPDEFINES'] = CPPDEFINES = successflags.get('CPPDEFINES', []).copy()
 		# use Redbook if at least one of the following applies
@@ -4608,3 +4608,3 @@
 		for test in runtime_test_boost_tests:
-			LIBS = [] if test.nodefaultlibs else env['LIBS'][:]
+			LIBS = [] if test.nodefaultlibs else env['LIBS'].copy()
 			LIBS.append('boost_unit_test_framework')
@@ -4850,3 +4850,3 @@
 			kwargs['CXXFLAGS'] = (env['CXXFLAGS'] or []) + ['-E']
-			kwargs['CPPDEFINES'] = (env['CPPDEFINES'] or []) + [
+			kwargs['CPPDEFINES'] = list(env['CPPDEFINES'] or []) + [
 					# Define these tokens to themselves so that
@@ -4870,3 +4870,3 @@
 	def _apply_env_version_seq(self,env,_empty={}):
-		return _empty if self.user_settings.pch else {'CPPDEFINES' : env['CPPDEFINES'] + [('DXX_VERSION_SEQ', self.DXX_VERSION_SEQ)]}
+		return _empty if self.user_settings.pch else {'CPPDEFINES' : list(env['CPPDEFINES']) + [('DXX_VERSION_SEQ', self.DXX_VERSION_SEQ)]}
 	get_objects_similar_arch_ogl = DXXCommon.create_lazy_object_states_getter((LazyObjectState(sources=(
@@ -4966,3 +4966,3 @@
 ),
-		transform_env = (lambda self, env: {'CPPDEFINES' : env['CPPDEFINES'] + env.__dxx_CPPDEFINE_SHAREPATH + env.__dxx_CPPDEFINE_git_version}),
+		transform_env = (lambda self, env: {'CPPDEFINES' : list(env['CPPDEFINES']) + env.__dxx_CPPDEFINE_SHAREPATH + env.__dxx_CPPDEFINE_git_version}),
 		transform_target=_apply_target_name,
@@ -4976,3 +4976,3 @@
 ),
-		transform_env = (lambda self, env: {'CPPDEFINES' : env['CPPDEFINES'] + env.__dxx_CPPDEFINE_SHAREPATH}),
+		transform_env = (lambda self, env: {'CPPDEFINES' : list(env['CPPDEFINES']) + env.__dxx_CPPDEFINE_SHAREPATH}),
 		transform_target=_apply_target_name,
@@ -5185,3 +5185,3 @@
 		versid_build_environ = ['CXX', 'CPPFLAGS', 'CXXFLAGS', 'LINKFLAGS']
-		versid_cppdefines = env['CPPDEFINES'][:]
+		versid_cppdefines = env['CPPDEFINES'].copy()
 		extra_version = user_settings.extra_version
@@ -5303,3 +5303,3 @@
 		else:
-			syspath = sys.path[:]
+			syspath = sys.path.copy()
 			cocoa = 'common/arch/cocoa'