[ARC] Define LINK_GCC_C_SEQUENCE_SPEC.

If no specs file is provided, default to nosys library.

gcc/
2017-05-03  Claudiu Zissulescu  <claziss@synopsys.com>

	* config/arc/elf.h (LINK_GCC_C_SEQUENCE_SPEC): Define.

From-SVN: r261541

gcc/ChangeLog

 2018-06-12  Claudiu Zissulescu  <claziss@synopsys.com>
 
+	* config/arc/elf.h (LINK_GCC_C_SEQUENCE_SPEC): Define.
+
+2018-06-12  Claudiu Zissulescu  <claziss@synopsys.com>
+
 	* config/arc/builtins.def (SYNC): SYNC instruction is valid on all
 	ARC cores.
 

gcc/config/arc/elf.h

@@ -73,3 +73,8 @@ along with GCC; see the file COPYING3.  If not see
 
 #undef TARGET_ASM_FILE_END
 #define TARGET_ASM_FILE_END arc_file_end
+
+/* If no specs file is enforced, default to nosys libarary.  */
+#undef LINK_GCC_C_SEQUENCE_SPEC
+#define LINK_GCC_C_SEQUENCE_SPEC				\
+  "--start-group %G %{!specs=*:-lc -lnosys} --end-group"