Downgrade SDL to 2.0.8 for Windows

Revert "Update SDL (2.0.9) for Windows"

Several users experienced freezes with SDL 2.0.9.

This reverts commit a5787dccd6.

See:
 - <https://github.com/Genymobile/scrcpy/issues/425>
 - <https://discourse.libsdl.org/t/unstable-frame-rate-unexpectedly/25783>

Makefile.CrossWindows

@@ -107,7 +107,7 @@ dist-win32: build-server build-win32 build-win32-noconsole
 	cp prebuilt-deps/platform-tools/adb.exe "$(DIST)/$(WIN32_TARGET_DIR)/"
 	cp prebuilt-deps/platform-tools/AdbWinApi.dll "$(DIST)/$(WIN32_TARGET_DIR)/"
 	cp prebuilt-deps/platform-tools/AdbWinUsbApi.dll "$(DIST)/$(WIN32_TARGET_DIR)/"
-	cp prebuilt-deps/SDL2-2.0.9/i686-w64-mingw32/bin/SDL2.dll "$(DIST)/$(WIN32_TARGET_DIR)/"
+	cp prebuilt-deps/SDL2-2.0.8/i686-w64-mingw32/bin/SDL2.dll "$(DIST)/$(WIN32_TARGET_DIR)/"
 
 dist-win64: build-server build-win64 build-win64-noconsole
 	mkdir -p "$(DIST)/$(WIN64_TARGET_DIR)"
@@ -122,7 +122,7 @@ dist-win64: build-server build-win64 build-win64-noconsole
 	cp prebuilt-deps/platform-tools/adb.exe "$(DIST)/$(WIN64_TARGET_DIR)/"
 	cp prebuilt-deps/platform-tools/AdbWinApi.dll "$(DIST)/$(WIN64_TARGET_DIR)/"
 	cp prebuilt-deps/platform-tools/AdbWinUsbApi.dll "$(DIST)/$(WIN64_TARGET_DIR)/"
-	cp prebuilt-deps/SDL2-2.0.9/x86_64-w64-mingw32/bin/SDL2.dll "$(DIST)/$(WIN64_TARGET_DIR)/"
+	cp prebuilt-deps/SDL2-2.0.8/x86_64-w64-mingw32/bin/SDL2.dll "$(DIST)/$(WIN64_TARGET_DIR)/"
 
 zip-win32: dist-win32
 	cd "$(DIST)"; \

cross_win32.txt

@@ -17,4 +17,4 @@ endian = 'little'
 [properties]
 prebuilt_ffmpeg_shared = 'ffmpeg-4.1.3-win32-shared'
 prebuilt_ffmpeg_dev = 'ffmpeg-4.1.3-win32-dev'
-prebuilt_sdl2 = 'SDL2-2.0.9/i686-w64-mingw32'
+prebuilt_sdl2 = 'SDL2-2.0.8/i686-w64-mingw32'

cross_win64.txt

@@ -17,4 +17,4 @@ endian = 'little'
 [properties]
 prebuilt_ffmpeg_shared = 'ffmpeg-4.1.3-win64-shared'
 prebuilt_ffmpeg_dev = 'ffmpeg-4.1.3-win64-dev'
-prebuilt_sdl2 = 'SDL2-2.0.9/x86_64-w64-mingw32'
+prebuilt_sdl2 = 'SDL2-2.0.8/x86_64-w64-mingw32'

prebuilt-deps/Makefile

@@ -30,9 +30,9 @@ prepare-ffmpeg-dev-win64:
 		ffmpeg-4.1.3-win64-dev
 
 prepare-sdl2:
-	@./prepare-dep https://libsdl.org/release/SDL2-devel-2.0.9-mingw.tar.gz \
-		0f9f00d0f2a9a95dfb5cce929718210c3f85432cc2e9d4abade4adcb7f6bb39d \
-		SDL2-2.0.9
+	@./prepare-dep https://libsdl.org/release/SDL2-devel-2.0.8-mingw.tar.gz \
+		ffff7305d634aff5e1df5b7bb935435c3a02c8b03ad94a1a2be9169a558a7961 \
+		SDL2-2.0.8
 
 prepare-adb:
 	@./prepare-dep https://dl.google.com/android/repository/platform-tools_r28.0.1-windows.zip \