libretro: add aarch64 to ARCH, remove aarch64 specific code

pkgs/applications/emulators/retroarch/cores.nix

@@ -400,8 +400,6 @@ in
     core = "flycast";
     extraBuildInputs = [ libGL libGLU ];
     makefile = "Makefile";
-    makeFlags = lib.optionals stdenv.hostPlatform.isAarch64 [ "platform=arm64" ];
-    patches = [ ./fix-flycast-makefile.patch ];
     meta = {
       description = "Flycast libretro port";
       license = lib.licenses.gpl2Only;
@@ -735,7 +733,6 @@ in
   picodrive = mkLibretroCore {
     core = "picodrive";
     dontConfigure = true;
-    makeFlags = lib.optionals stdenv.hostPlatform.isAarch64 [ "platform=aarch64" ];
     meta = {
       description = "Fast MegaDrive/MegaCD/32X emulator";
       license = "MAME";

pkgs/applications/emulators/retroarch/fix-flycast-makefile.patch

@@ -1,12 +0,0 @@
-diff --git a/Makefile b/Makefile
-index 01d99c30..8c2dd248 100644
---- a/Makefile
-+++ b/Makefile
-@@ -440,7 +440,6 @@ else ifeq ($(platform), arm64)
- 	CPUFLAGS += -DTARGET_LINUX_ARMv8 -frename-registers
- 	CFLAGS += $(CPUFLAGS)
- 	CXXFLAGS += $(CPUFLAGS)
--	ASFLAGS += $(CFLAGS) -c -frename-registers -fno-strict-aliasing -ffast-math -ftree-vectorize
- 	PLATFORM_EXT := unix
- 	WITH_DYNAREC=arm64
- 	HAVE_GENERIC_JIT = 0

pkgs/applications/emulators/retroarch/mkLibretroCore.nix

@@ -53,6 +53,7 @@ stdenv.mkDerivation ({
     "ARCH=${{
       armv7l = "arm";
       armv6l = "arm";
+      aarch64 = "arm64";
       i686 = "x86";
     }.${stdenv.hostPlatform.parsed.cpu.name} or stdenv.hostPlatform.parsed.cpu.name}"
   ] ++ (args.makeFlags or [ ]);