--- old/make/lib/Awt2dLibraries.gmk	2018-02-07 23:28:59.394216287 +0100
+++ new/make/lib/Awt2dLibraries.gmk	2018-02-07 23:28:59.094205766 +0100
@@ -358,7 +358,8 @@
         WARNINGS_AS_ERRORS_xlc := false, \
         DISABLED_WARNINGS_gcc := type-limits pointer-to-int-cast \
             unused-result maybe-uninitialized format \
-            format-security int-to-pointer-cast parentheses, \
+            format-security int-to-pointer-cast parentheses \
+            implicit-fallthrough, \
         DISABLED_WARNINGS_solstudio := E_DECLARATION_IN_CODE \
             E_ASSIGNMENT_TYPE_MISMATCH E_NON_CONST_INIT, \
         MAPFILE := $(TOPDIR)/make/mapfiles/libawt_xawt/mapfile-vers, \
@@ -491,7 +492,7 @@
     CFLAGS := $(CFLAGS_JDKLIB) $(BUILD_LIBJAVAJPEG_HEADERS) \
         $(LIBJAVA_HEADER_FLAGS) \
         -I$(SUPPORT_OUTPUTDIR)/headers/java.desktop, \
-    DISABLED_WARNINGS_gcc := clobbered, \
+    DISABLED_WARNINGS_gcc := clobbered implicit-fallthrough shift-negative-value, \
     MAPFILE := $(TOPDIR)/make/mapfiles/libjpeg/mapfile-vers, \
     LDFLAGS := $(LDFLAGS_JDKLIB) \
         $(call SET_SHARED_LIBRARY_ORIGIN), \
@@ -669,7 +670,7 @@
     CFLAGS_windows = -DCC_NOEX, \
     WARNINGS_AS_ERRORS_xlc := false, \
     DISABLED_WARNINGS_gcc := sign-compare int-to-pointer-cast \
-        type-limits missing-field-initializers, \
+        type-limits missing-field-initializers implicit-fallthrough, \
     DISABLED_WARNINGS_CXX_gcc := reorder delete-non-virtual-dtor strict-overflow \
         maybe-uninitialized, \
     DISABLED_WARNINGS_clang := unused-value incompatible-pointer-types \
@@ -943,7 +944,8 @@
       OPTIMIZATION := LOW, \
       CFLAGS := $(LIBSPLASHSCREEN_CFLAGS) $(CFLAGS_JDKLIB) \
           $(GIFLIB_CFLAGS) $(LIBJPEG_CFLAGS) $(PNG_CFLAGS) $(LIBZ_CFLAGS), \
-      DISABLED_WARNINGS_gcc := sign-compare type-limits unused-result maybe-uninitialized shift-negative-value, \
+      DISABLED_WARNINGS_gcc := sign-compare type-limits unused-result \
+          maybe-uninitialized shift-negative-value implicit-fallthrough, \
       DISABLED_WARNINGS_clang := incompatible-pointer-types, \
       DISABLED_WARNINGS_solstudio := E_NEWLINE_NOT_LAST E_DECLARATION_IN_CODE \
           E_STATEMENT_NOT_REACHED, \