Build: Add Cortex-M85 cpu support with GCC13

Signed-off-by: Dávid Házi <david.hazi@arm.com>
Change-Id: Ia41d246b7acfa538b4023a023cb1277f1a08f8b0
diff --git a/toolchain_GNUARM.cmake b/toolchain_GNUARM.cmake
index c65734e..b6ae50e 100644
--- a/toolchain_GNUARM.cmake
+++ b/toolchain_GNUARM.cmake
@@ -29,13 +29,16 @@
 # with the Ninja generator.
 set(CMAKE_USER_MAKE_RULES_OVERRIDE ${CMAKE_CURRENT_LIST_DIR}/cmake/set_extensions.cmake)
 
+# CMAKE_C_COMPILER_VERSION is not guaranteed to be defined.
+EXECUTE_PROCESS( COMMAND ${CMAKE_C_COMPILER} -dumpversion OUTPUT_VARIABLE GCC_VERSION )
+
 # ===================== SEt toolchain CPU and Arch =============================
 
 if (DEFINED TFM_SYSTEM_PROCESSOR)
-    if(TFM_SYSTEM_PROCESSOR MATCHES "cortex-m85")
-        # GNUARM does not support the -mcpu=cortex-m85 flag yet
-        # TODO: Remove this exception when the cortex-m85 support comes out.
-        message(WARNING "Cortex-m85 is not supported by GCC. Falling back to -march usage.")
+    if(TFM_SYSTEM_PROCESSOR MATCHES "cortex-m85" AND GCC_VERSION VERSION_LESS "13.0.0")
+        # GNUARM until version 13 does not support the -mcpu=cortex-m85 flag
+        message(WARNING "Cortex-m85 is only supported from GCC13. "
+                        "Falling back to -march usage for earlier versions.")
     else()
         set(CMAKE_SYSTEM_PROCESSOR ${TFM_SYSTEM_PROCESSOR})
 
@@ -102,9 +105,6 @@
     endif()
 endif()
 
-# CMAKE_C_COMPILER_VERSION is not guaranteed to be defined.
-EXECUTE_PROCESS( COMMAND ${CMAKE_C_COMPILER} -dumpversion OUTPUT_VARIABLE GCC_VERSION )
-
 add_compile_options(
     -specs=nano.specs
     -Wall