Set rv64gc as default --with-arch option.

Author: pz9115

configure

@@ -1398,7 +1398,7 @@ Optional Features:
 Optional Packages:
   --with-PACKAGE[=ARG]    use PACKAGE [ARG=yes]
   --without-PACKAGE       do not use PACKAGE (same as --with-PACKAGE=no)
-  --with-arch=rv64imafdc  Sets the base RISC-V ISA, defaults to rv64imafdc
+  --with-arch=rv64gc      Sets the base RISC-V ISA, defaults to rv64gc
   --with-abi=lp64d        Sets the base RISC-V ABI, defaults to lp64d
   --with-tune=rocket      Set the base RISC-V CPU, defaults to rocket
   --with-isa-spec=20191213
@@ -3993,7 +3993,7 @@ if test ${with_arch+y}
 then :
   withval=$with_arch;
 else $as_nop
-  with_arch=rv64imafdc
+  with_arch=rv64gc
 
 fi
 

configure.ac

@@ -80,10 +80,10 @@ AS_IF([test "x$enable_default_pie" != xyes],
 
 
 AC_ARG_WITH(arch,
-	[AS_HELP_STRING([--with-arch=rv64imafdc],
-		[Sets the base RISC-V ISA, defaults to rv64imafdc])],
+	[AS_HELP_STRING([--with-arch=rv64gc],
+		[Sets the base RISC-V ISA, defaults to rv64gc])],
 	[],
-	[with_arch=rv64imafdc]
+	[with_arch=rv64gc]
 	)
 
 AC_ARG_WITH(abi,