diff --git a/winsup/utils/Makefile.in b/winsup/utils/Makefile.in
index 6bf4454c5..248939645 100644
--- a/winsup/utils/Makefile.in
+++ b/winsup/utils/Makefile.in
@@ -14,9 +14,11 @@ configure_args=@configure_args@
 export CC:=@CC@
 export CXX:=@CXX@
 
+CFLAGS_COMMON=-Wimplicit-fallthrough=4 -Werror
 CFLAGS:=@CFLAGS@
 CXXFLAGS:=@CXXFLAGS@
-override CXXFLAGS+=-fno-exceptions -fno-rtti
+override CFLAGS+=${CFLAGS_COMMON}
+override CXXFLAGS+=-fno-exceptions -fno-rtti ${CFLAGS_COMMON}
 
 include ${srcdir}/../Makefile.common
 
diff --git a/winsup/utils/ssp.c b/winsup/utils/ssp.c
index 779b31775..4c98eefa9 100644
--- a/winsup/utils/ssp.c
+++ b/winsup/utils/ssp.c
@@ -465,7 +465,7 @@ run_program (char *cmdline)
 		      thread_return_address[tix] = rv;
 		}
 	      set_step_threads (event.dwThreadId, stepping_enabled);
-	      /* fall-through */
+	      /*FALLTHRU*/
 	    case STATUS_SINGLE_STEP:
 	      opcode_count++;
 	      pc = (CONTEXT_REG)event.u.Exception.ExceptionRecord.ExceptionAddress;