--- old/make/launcher/Launcher-jdk.pack.gmk	2018-06-13 22:05:40.828049396 +0530
+++ new/make/launcher/Launcher-jdk.pack.gmk	2018-06-13 22:05:40.696049391 +0530
@@ -90,7 +90,6 @@
     CFLAGS_linux := -fPIC, \
     CFLAGS_solaris := -KPIC, \
     CFLAGS_macosx := -fPIC, \
-    DISABLED_WARNINGS_gcc := unused-result implicit-fallthrough, \
     LDFLAGS := $(UNPACKEXE_ZIPOBJS) \
         $(LDFLAGS_JDKEXE) $(LDFLAGS_CXX_JDK) \
         $(call SET_SHARED_LIBRARY_ORIGIN), \
--- old/src/jdk.pack/share/native/common-unpack/unpack.cpp	2018-06-13 22:05:41.188049409 +0530
+++ new/src/jdk.pack/share/native/common-unpack/unpack.cpp	2018-06-13 22:05:41.056049404 +0530
@@ -1799,6 +1799,7 @@
     case 'B': case 'H': case 'I': case 'V': // unsigned_int
     case 'S': // signed_int
       --lp; // reparse
+      /* fall through */
     case 'F':
       lp = parseIntLayout(lp, b, EK_INT);
       break;
@@ -3710,6 +3711,7 @@
     if (value.b.ptr == null)
       return ref(0)->string();
     // else fall through:
+    /* fall through */
   case CONSTANT_Utf8:
     buf = value.b;
     break;
@@ -4216,6 +4218,7 @@
         case _invokeinit_self_option:   classRef = thisClass;  break;
         case _invokeinit_super_option:  classRef = superClass; break;
         default: assert(bc == _invokeinit_op+_invokeinit_new_option);
+        /* fall through */
         case _invokeinit_new_option:    classRef = newClass;   break;
         }
         wp[-1] = origBC;  // overwrite with origBC
--- old/src/jdk.pack/share/native/common-unpack/zip.cpp	2018-06-13 22:05:41.576049424 +0530
+++ new/src/jdk.pack/share/native/common-unpack/zip.cpp	2018-06-13 22:05:41.444049419 +0530
@@ -533,6 +533,8 @@
   char* bufptr = (char*) buf;
   char* inbuf = u->gzin->inbuf;
   size_t inbuflen = sizeof(u->gzin->inbuf);
+  // capture return values from fread to avoid -Werror=unused-result issues
+  size_t ret = 0;
   unpacker::read_input_fn_t read_gzin_fn =
     (unpacker::read_input_fn_t) u->gzin->read_input_fn;
   z_stream& zs = *(z_stream*) u->gzin->zstream;
@@ -579,8 +581,8 @@
         fseek(u->infileptr, -TRAILER_LEN, SEEK_END);
         uint filecrc;
         uint filelen;
-        fread(&filecrc, sizeof(filecrc), 1, u->infileptr);
-        fread(&filelen, sizeof(filelen), 1, u->infileptr);
+        ret = fread(&filecrc, sizeof(filecrc), 1, u->infileptr);
+        ret = fread(&filelen, sizeof(filelen), 1, u->infileptr);
         filecrc = SWAP_INT(filecrc);
         filelen = SWAP_INT(filelen);
         if (u->gzin->gzcrc != filecrc ||