Upgrade Android NDK to r23 LTS

SConstruct

@@ -103,11 +103,13 @@ custom_tools = ["default"]
 
 platform_arg = ARGUMENTS.get("platform", ARGUMENTS.get("p", False))
 
-if os.name == "nt" and (platform_arg == "android" or methods.get_cmdline_bool("use_mingw", False)):
-    custom_tools = ["mingw"]
+if platform_arg == "android":
+    custom_tools = ["clang", "clang++", "as", "ar", "link"]
 elif platform_arg == "javascript":
     # Use generic POSIX build toolchain for Emscripten.
     custom_tools = ["cc", "c++", "ar", "link", "textfile", "zip"]
+elif os.name == "nt" and methods.get_cmdline_bool("use_mingw", False):
+    custom_tools = ["mingw"]
 
 # We let SCons build its default ENV as it includes OS-specific things which we don't
 # want to have to pull in manually.
@@ -395,10 +397,7 @@ if selected_platform in platform_list:
     sys.path.insert(0, tmppath)
     import detect
 
-    if "create" in dir(detect):
-        env = detect.create(env_base)
-    else:
-        env = env_base.Clone()
+    env = env_base.Clone()
 
     if env["compiledb"]:
         # Generating the compilation DB (`compile_commands.json`) requires SCons 4.0.0 or later.