Add ios-arm64 build target; Added forward declarations for a couple c…

…ompression related methods needed to fix compile issues; fixing zlib header for ios-arm64

Makefile.libretro

@@ -149,10 +149,16 @@ else ifneq (,$(findstring ios,$(platform)))
 		IOSSDK := $(shell xcodebuild -version -sdk iphoneos Path)
 	endif
 
+ifeq ($(platform),ios-arm64)
+	CC = cc -arch arm64 -isysroot $(IOSSDK)
+	CXX = c++ -arch arm64 -isysroot $(IOSSDK)
+else
 	CC = cc -arch armv7 -isysroot $(IOSSDK)
-	CC_AS = perl ./tools/gas-preprocessor.pl $(CC)
 	CXX = c++ -arch armv7 -isysroot $(IOSSDK)
-ifeq ($(platform),ios9)
+endif
+	CC_AS = perl ./tools/gas-preprocessor.pl $(CC)
+
+ifeq ($(platform),$(filter $(platform),ios9 ios-arm64))
 	CC += -miphoneos-version-min=8.0
 	CXX += -miphoneos-version-min=8.0
 	CC_AS += -miphoneos-version-min=8.0
@@ -164,6 +170,10 @@ else
 	PLATFORM_DEFINES := -miphoneos-version-min=5.0
 endif
 
+ifeq ($(platform),ios-arm64)
+	PLATFORM_DEFINES += -D_IOS_ARM64
+endif
+
 # Theos
 else ifeq ($(platform), theos_ios)
 	DEPLOYMENT_IOSVERSION = 5.0

libspectrum/internals.h

@@ -102,6 +102,14 @@ libspectrum_error
 libspectrum_bzip2_inflate( const libspectrum_byte *bzptr, size_t bzlength,
 			   libspectrum_byte **outptr, size_t *outlength );
 
+libspectrum_error
+libspectrum_zlib_inflate( const libspectrum_byte *gzptr, size_t gzlength,
+        libspectrum_byte **outptr, size_t *outlength );
+
+libspectrum_error
+libspectrum_zlib_compress( const libspectrum_byte *data, size_t length,
+         libspectrum_byte **gzptr, size_t *gzlength );
+
 /* The TZX file signature */
 
 extern const char *libspectrum_tzx_signature;

zlib/gzguts.h

@@ -18,6 +18,10 @@
 #  define ZLIB_INTERNAL
 #endif
 
+#ifdef _IOS_ARM64
+#include <unistd.h>
+#endif
+
 #include <stdio.h>
 #include "zlib.h"
 #ifdef STDC