configure: Add Apple Silicon support

config.guess

@@ -1238,6 +1238,9 @@ EOF
     *:Rhapsody:*:*)
 	echo ${UNAME_MACHINE}-apple-rhapsody${UNAME_RELEASE}
 	exit ;;
+    arm64:Darwin:*:*)
+	echo arm64-apple-darwin${UNAME_RELEASE}
+	exit ;;
     *:Darwin:*:*)
 	UNAME_PROCESSOR=`uname -p` || UNAME_PROCESSOR=unknown
 	case $UNAME_PROCESSOR in

config.sub

@@ -255,7 +255,7 @@ case $basic_machine in
 	# Some are omitted here because they have special meanings below.
 	1750a | 580 \
 	| a29k \
-	| aarch64 | aarch64_be \
+	| aarch64 | aarch64_be | arm64 \
 	| alpha | alphaev[4-8] | alphaev56 | alphaev6[78] | alphapca5[67] \
 	| alpha64 | alpha64ev[4-8] | alpha64ev56 | alpha64ev6[78] | alpha64pca5[67] \
 	| am33_2.0 \
@@ -369,7 +369,7 @@ case $basic_machine in
 	# Recognize the basic CPU types with company name.
 	580-* \
 	| a29k-* \
-	| aarch64-* | aarch64_be-* \
+	| aarch64-* | aarch64_be-* | arm64*-* \
 	| alpha-* | alphaev[4-8]-* | alphaev56-* | alphaev6[78]-* \
 	| alpha64-* | alpha64ev[4-8]-* | alpha64ev56-* | alpha64ev6[78]-* \
 	| alphapca5[67]-* | alpha64pca5[67]-* | arc-* \

configure

@@ -821,6 +821,18 @@ case $host_cpu in
         AS="${AS-${CC}}"
         AS_EXT=".c"
         ;;
+    aarch64|arm64*)
+        ARCH="AARCH64"
+        stack_alignment=16
+        if [ "$SYS" = MACOSX ] ; then
+            AS="${AS-${CC}}"
+            ASFLAGS="$ASFLAGS -DPREFIX -DPIC"
+        elif [ "$SYS" = WINDOWS ] && [ "$compiler" = CL ] ; then
+            AS="${AS-${SRCPATH}/tools/gas-preprocessor.pl -arch aarch64 -as-type armasm -- armasm64 -nologo}"
+        else
+            AS="${AS-${CC}}"
+        fi
+        ;;
     arm*)
         ARCH="ARM"
         if [ "$SYS" = MACOSX ] ; then
@@ -839,18 +851,6 @@ case $host_cpu in
             AS="${AS-${CC}}"
         fi
         ;;
-    aarch64)
-        ARCH="AARCH64"
-        stack_alignment=16
-        if [ "$SYS" = MACOSX ] ; then
-            AS="${AS-${CC}}"
-            ASFLAGS="$ASFLAGS -DPREFIX -DPIC"
-        elif [ "$SYS" = WINDOWS ] && [ "$compiler" = CL ] ; then
-            AS="${AS-${SRCPATH}/tools/gas-preprocessor.pl -arch aarch64 -as-type armasm -- armasm64 -nologo}"
-        else
-            AS="${AS-${CC}}"
-        fi
-        ;;
     s390|s390x)
         ARCH="S390"
         ;;