opcache/jit support: Mac M1 build fic

unfortunately host_cpu is set only as `arm`.
adding preprocessor ARM64APPLE for future use to be able to distinguish
 possibly from an usual arm64 board (e.g. not all same registers,
x29/x30 vs fp/lr etc).

Author: devnexen

ext/opcache/config.m4

@@ -22,14 +22,15 @@ if test "$PHP_OPCACHE" != "no"; then
 
   dnl Always build as shared extension
   ext_shared=yes
+  uname_m=`uname -m 2>/dev/null`
 
   if test "$PHP_HUGE_CODE_PAGES" = "yes"; then
     AC_DEFINE(HAVE_HUGE_CODE_PAGES, 1, [Define to enable copying PHP CODE pages into HUGE PAGES (experimental)])
   fi
 
   if test "$PHP_OPCACHE_JIT" = "yes"; then
-    case $host_cpu in
-      i[34567]86*|x86*|aarch64)
+    case $uname_m in
+      i[34567]86*|x86*|aarch64|arm64)
         ;;
       *)
         AC_MSG_WARN([JIT not supported by host architecture])
@@ -58,6 +59,10 @@ if test "$PHP_OPCACHE" != "no"; then
       x86*)
         DASM_ARCH="x86"
         ;;
+      arm*-*-darwin*)
+        DASM_FLAGS="-D ARM64APPLE=1 -D ARM64=1"
+        DASM_ARCH="arm64"
+        ;;
       aarch64*)
         DASM_FLAGS="-D ARM64=1"
         DASM_ARCH="arm64"