Add ARMv9.2-a arch option.

Bug: 364383722
Test: presubmit
Change-Id: Ica7266f6dbac490836f94f7e19685383aba2749f
diff --git a/android/arch_list.go b/android/arch_list.go
index f1289a3..2937092 100644
--- a/android/arch_list.go
+++ b/android/arch_list.go
@@ -159,6 +159,9 @@
 		"armv9-a": {
 			"dotprod",
 		},
+		"armv9-2a": {
+			"dotprod",
+		},
 	},
 	X86: {
 		"amberlake": {
diff --git a/cc/config/arm64_device.go b/cc/config/arm64_device.go
index beb68e1..761afcf 100644
--- a/cc/config/arm64_device.go
+++ b/cc/config/arm64_device.go
@@ -41,11 +41,18 @@
 		"armv8-2a-dotprod": []string{
 			"-march=armv8.2-a+dotprod",
 		},
+		// On ARMv9 and later, Pointer Authentication Codes (PAC) are mandatory,
+		// so -fstack-protector is unnecessary.
 		"armv9-a": []string{
 			"-march=armv8.2-a+dotprod",
 			"-mbranch-protection=standard",
 			"-fno-stack-protector",
 		},
+		"armv9-2a": []string{
+			"-march=armv9.2-a",
+			"-mbranch-protection=standard",
+			"-fno-stack-protector",
+		},
 	}
 
 	arm64Ldflags = []string{