aarch64: libgcc: add GCS marking to asm

libgcc/ChangeLog:

	* config/aarch64/aarch64-asm.h (FEATURE_1_GCS): Define.
	(GCS_FLAG): Define if GCS is enabled.
	(GNU_PROPERTY): Add GCS_FLAG.

libgcc/config/aarch64/aarch64-asm.h

@@ -22,6 +22,9 @@
    see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
    <http://www.gnu.org/licenses/>.  */
 
+#ifndef AARCH64_ASM_H
+#define AARCH64_ASM_H
+
 #include "auto-target.h"
 
 #define L(label) .L ## label
@@ -38,6 +41,7 @@
 #define FEATURE_1_AND 0xc0000000
 #define FEATURE_1_BTI 1
 #define FEATURE_1_PAC 2
+#define FEATURE_1_GCS 4
 
 /* Supported features based on the code generation options.  */
 #if defined(__ARM_FEATURE_BTI_DEFAULT)
@@ -58,6 +62,12 @@
 # define AUTIASP
 #endif
 
+#if __ARM_FEATURE_GCS_DEFAULT
+# define GCS_FLAG FEATURE_1_GCS
+#else
+# define GCS_FLAG 0
+#endif
+
 #ifdef __ELF__
 #define HIDDEN(name) .hidden name
 #define SYMBOL_SIZE(name) .size name, .-name
@@ -88,8 +98,8 @@
 .previous
 
 /* Add GNU property note if built with branch protection.  */
-# if (BTI_FLAG|PAC_FLAG) != 0
-GNU_PROPERTY (FEATURE_1_AND, BTI_FLAG|PAC_FLAG)
+# if (BTI_FLAG|PAC_FLAG|GCS_FLAG) != 0
+GNU_PROPERTY (FEATURE_1_AND, BTI_FLAG|PAC_FLAG|GCS_FLAG)
 # endif
 #endif
 
@@ -106,3 +116,5 @@ GNU_PROPERTY (FEATURE_1_AND, BTI_FLAG|PAC_FLAG)
 #define END(name) \
   .cfi_endproc;		\
   SYMBOL_SIZE(name)
+
+#endif