Bundle different versions of SDL for Windows and MacOS.

This puts off issues I've been having with MacOS.

Author: HexDecimal

CHANGELOG.rst

@@ -8,6 +8,11 @@ v2.0.0
 
 Unreleased
 ------------------
+Changed
+ - Now bundles SDL 2.0.10 for MacOS and SDL 2.0.14 for Windows.
+
+Fixed
+ - MacOS wheels were failing to bundle dependencies for SDL2.
 
 11.19.1 - 2020-12-29
 --------------------

build_libtcod.py

@@ -23,8 +23,13 @@
 
 # The SDL2 version to parse and export symbols from.
 SDL2_PARSE_VERSION = os.environ.get("SDL_VERSION", "2.0.5")
+
 # The SDL2 version to include in binary distributions.
-SDL2_BUNDLE_VERSION = os.environ.get("SDL_VERSION", "2.0.14")
+# MacOS delocate-wheel will fail without throwing an error when bundling
+# modern versions of SDL.
+SDL2_BUNDLE_VERSION = os.environ.get(
+    "SDL_VERSION", "2.0.10" if sys.platform == "darwin" else "2.0.14"
+)
 
 HEADER_PARSE_PATHS = ("tcod/", "libtcod/src/libtcod/")
 HEADER_PARSE_EXCLUDES = ("gl2_ext_.h", "renderer_gl_internal.h", "event.h")