--- /dev/null
+diff --git a/mingw-w64-tools/gendef/src/gendef.c b/mingw-w64-tools/gendef/src/gendef.c
+index a935abfe..cefdd8cb 100644
+--- a/mingw-w64-tools/gendef/src/gendef.c
++++ b/mingw-w64-tools/gendef/src/gendef.c
+@@ -1031,13 +1031,16 @@ redo_switch:
+ PRDEBUG(" 0x%x illegal ", (unsigned int) b);
+ #endif
+ *aCode=c_ill; return 0;
+- case c_4: sz++;
+- case c_3: sz++;
+- case c_lb:
+- case c_2: sz++;
+- case c_retn: case c_retf:
+- case c_iret: case c_int3:
+- case c_ad: case c_op:
++ case c_4: sz++; // fallthrough
++ case c_3: sz++; // fallthrough
++ case c_lb: // fallthrough
++ case c_2: sz++; // fallthrough
++ case c_retn: // fallthrough
++ case c_retf: // fallthrough
++ case c_iret: // fallthrough
++ case c_int3: // fallthrough
++ case c_ad: // fallthrough
++ case c_op: // fallthrough
+ case c_1: *aCode=tb1; return sz;
+ case c_lv:
+ if (oper_mode) sz+=4;
+diff --git a/mingw-w64-tools/genpeimg/src/genpeimg.c b/mingw-w64-tools/genpeimg/src/genpeimg.c
+index b2430bbc..6a37b1a0 100644
+--- a/mingw-w64-tools/genpeimg/src/genpeimg.c
++++ b/mingw-w64-tools/genpeimg/src/genpeimg.c
+@@ -203,7 +203,7 @@ pass_args (int argc, char **argv)
+ goto error_point;
+ case 'h':
+ if (h[2] == 0)
+- show_usage ();
++ show_usage (); // fallthrough
+ default:
+ error_point:
+ fprintf (stderr, "Unknown option ,%s'\n", h);