Squashed 'src/leveldb/' changes from aca1ffc..ae6c262

ae6c262 Merge branch 'leveldb' into ripple-fork
28fa222 Looks like a bit more delay is needed to smooth the latency.
a18f3e6 Tidy up JobQueue, add ripple_core module
ab82e57 Release leveldb 1.12
02c6259 Release leveldb 1.11
5bbb544 Rate limit compactions with a 25ms pause after each complete file.
8c29c47 LevelDB issue 178 fix: cannot resize a level 0 compaction set
18b245c Added GNU/kFreeBSD kernel name (TARGET_OS)
8be9d12 CondVar::SignalAll was broken, leading to deadlocks on Windows builds. http://code.google.com/p/leveldb/issues/detail?id=149
c9fc070 Upgrade LevelDB to 1.10.0, mostly for better write stall logging.
8215b15 Tweak to variable name to support unity build

git-subtree-dir: src/leveldb
git-subtree-split: ae6c2620b2ef3d5c69e63dc0eda865d6a39fa061

util/hash.cc

@@ -6,6 +6,13 @@
 #include "util/coding.h"
 #include "util/hash.h"
 
+// The FALLTHROUGH_INTENDED macro can be used to annotate implicit fall-through
+// between switch labels. The real definition should be provided externally.
+// This one is a fallback version for unsupported compilers.
+#ifndef FALLTHROUGH_INTENDED
+#define FALLTHROUGH_INTENDED do { } while (0)
+#endif
+
 namespace leveldb {
 
 uint32_t Hash(const char* data, size_t n, uint32_t seed) {
@@ -28,10 +35,10 @@ uint32_t Hash(const char* data, size_t n, uint32_t seed) {
   switch (limit - data) {
     case 3:
       h += data[2] << 16;
-      // fall through
+      FALLTHROUGH_INTENDED;
     case 2:
       h += data[1] << 8;
-      // fall through
+      FALLTHROUGH_INTENDED;
     case 1:
       h += data[0];
       h *= m;