diff --git a/manifest b/manifest
index cb1075550c..2ff5cbd73e 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Enhance\sthe\sinteger-comparison\soptimization\son\sthe\sOP_Eq\sand\ssimilar\nopcodes\sso\sthat\sit\savoids\sa\slot\sof\suseless\swork.
-D 2021-05-17T16:54:52.605
+C Fix\sharmless\scompiler\swarnings.
+D 2021-05-17T17:14:38.533
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
 F LICENSE.md df5091916dbb40e6e9686186587125e1b2ff51f022cc334e886c19a0e9982724
@@ -484,7 +484,7 @@ F src/auth.c 08954fdc4cc2da5264ba5b75cfd90b67a6fc7d1710a02ccf917c38eadec77853
 F src/backup.c 3014889fa06e20e6adfa0d07b60097eec1f6e5b06671625f476a714d2356513d
 F src/bitvec.c 17ea48eff8ba979f1f5b04cc484c7bb2be632f33
 F src/btmutex.c 8acc2f464ee76324bf13310df5692a262b801808984c1b79defb2503bbafadb6
-F src/btree.c f74511a1476175a734221d38e33638b6fc4c6c94c819bbfa8419824703b967da
+F src/btree.c 51ba86095316fceb3e25bc61617d673d84627e79f4ace83f8722910f33eedef3
 F src/btree.h 096cc53baa58be22b02c896d1cf933c38cfc6d65f9253c1367ece8cc88a24de5
 F src/btreeInt.h 7bc15a24a02662409ebcd6aeaa1065522d14b7fda71573a2b0568b458f514ae0
 F src/build.c 4e13b92f77d3f6dc1285c3636a2ba7c6af5cbb793e52075a762fbcebcd36e968
@@ -514,7 +514,7 @@ F src/mem1.c c12a42539b1ba105e3707d0e628ad70e611040d8f5e38cf942cee30c867083de
 F src/mem2.c b93b8762ab999a29ae7751532dadf0a1ac78040308a5fb1d17fcc365171d67eb
 F src/mem3.c 30301196cace2a085cbedee1326a49f4b26deff0af68774ca82c1f7c06fda4f6
 F src/mem5.c 9bf955937b07f8c32541c8a9991f33ce3173d944
-F src/memdb.c 41acf2b1a80a20b38a05f03711564b51c67e6dc376cc3f6b829ae644be25ad93
+F src/memdb.c 5028ea424597fcec4fa80e0302bf535af1c82de27c3af01682bd5762a990419a
 F src/memjournal.c 431c70a111223a8a6e2e7e9f014afc6c88d818d357d866afc563195f2277d50e
 F src/msvc.h 3a15918220367a8876be3fa4f2abe423a861491e84b864fb2b7426bf022a28f8
 F src/mutex.c 5e3409715552348732e97b9194abe92fdfcd934cfb681df4ba0ab87ac6c18d25
@@ -1913,7 +1913,7 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P 4c6cd54a8db78e5535912e76856bed4f797261aaca4248c69d2e2452194de297
-R 73d09b7d916ce62909b488068f093069
+P 4221f41af9df90da4183d45d0edfae19b4f7095ec35a203c8dfd2712799e3839
+R d5d98a0de42894b8e3a0e6933785a46c
 U drh
-Z 794872f0c0978da2cc0d2cc549058a5f
+Z 328f07f3b463752989563aff06a98cf6
diff --git a/manifest.uuid b/manifest.uuid
index 588120bdbd..ef36117f34 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-4221f41af9df90da4183d45d0edfae19b4f7095ec35a203c8dfd2712799e3839
\ No newline at end of file
+ace12a3912a4fdc2f0e741361ec705652a11b6f5e3548d54bd6f273671ba1e09
\ No newline at end of file
diff --git a/src/btree.c b/src/btree.c
index 66716254eb..300bb361e0 100644
--- a/src/btree.c
+++ b/src/btree.c
@@ -547,7 +547,6 @@ static void invalidateIncrblobCursors(
   int isClearTable        /* True if all rows are being deleted */
 ){
   BtCursor *p;
-  // if( pBtree->hasIncrblobCur==0 ) return;
   assert( pBtree->hasIncrblobCur );
   assert( sqlite3BtreeHoldsMutex(pBtree) );
   pBtree->hasIncrblobCur = 0;
diff --git a/src/memdb.c b/src/memdb.c
index b20d83bf03..4560d6ed65 100644
--- a/src/memdb.c
+++ b/src/memdb.c
@@ -152,7 +152,10 @@ static sqlite3_vfs memdb_vfs = {
   memdbSleep,                  /* xSleep */
   0, /* memdbCurrentTime, */   /* xCurrentTime */
   memdbGetLastError,           /* xGetLastError */
-  memdbCurrentTimeInt64        /* xCurrentTimeInt64 */
+  memdbCurrentTimeInt64,       /* xCurrentTimeInt64 */
+  0,                           /* xSetSystemCall */
+  0,                           /* xGetSystemCall */
+  0,                           /* xNextSystemCall */
 };
 
 static const sqlite3_io_methods memdb_io_methods = {
@@ -180,12 +183,21 @@ static const sqlite3_io_methods memdb_io_methods = {
 /*
 ** Enter/leave the mutex on a MemStore
 */
+#if defined(SQLITE_THREADSAFE) && SQLITE_THREADSAFE==0
+static void memdbEnter(MemStore *p){
+  UNUSED_PARAMETER(p);
+}
+static void memdbLeave(MemStore *p){
+  UNUSED_PARAMETER(p);
+}
+#else
 static void memdbEnter(MemStore *p){
   sqlite3_mutex_enter(p->pMutex);
 }
 static void memdbLeave(MemStore *p){
   sqlite3_mutex_leave(p->pMutex);
 }
+#endif
 
 
 
@@ -332,6 +344,8 @@ static int memdbTruncate(sqlite3_file *pFile, sqlite_int64 size){
 ** Sync an memdb-file.
 */
 static int memdbSync(sqlite3_file *pFile, int flags){
+  UNUSED_PARAMETER(pFile);
+  UNUSED_PARAMETER(flags);
   return SQLITE_OK;
 }
 
@@ -441,6 +455,7 @@ static int memdbSectorSize(sqlite3_file *pFile){
 ** Return the device characteristic flags supported by an memdb-file.
 */
 static int memdbDeviceCharacteristics(sqlite3_file *pFile){
+  UNUSED_PARAMETER(pFile);
   return SQLITE_IOCAP_ATOMIC | 
          SQLITE_IOCAP_POWERSAFE_OVERWRITE |
          SQLITE_IOCAP_SAFE_APPEND |
@@ -469,6 +484,8 @@ static int memdbFetch(
 /* Release a memory-mapped page */
 static int memdbUnfetch(sqlite3_file *pFile, sqlite3_int64 iOfst, void *pPage){
   MemStore *p = ((MemFile*)pFile)->pStore;
+  UNUSED_PARAMETER(iOfst);
+  UNUSED_PARAMETER(pPage);
   memdbEnter(p);
   p->nMmap--;
   memdbLeave(p);
@@ -581,6 +598,9 @@ static int memdbAccess(
   int flags, 
   int *pResOut
 ){
+  UNUSED_PARAMETER(pVfs);
+  UNUSED_PARAMETER(zPath);
+  UNUSED_PARAMETER(flags);
   *pResOut = 0;
   return SQLITE_OK;
 }
@@ -596,6 +616,7 @@ static int memdbFullPathname(
   int nOut, 
   char *zOut
 ){
+  UNUSED_PARAMETER(pVfs);
   sqlite3_snprintf(nOut, zOut, "%s", zPath);
   return SQLITE_OK;
 }
@@ -840,7 +861,7 @@ end_deserialize:
 */
 int sqlite3MemdbInit(void){
   sqlite3_vfs *pLower = sqlite3_vfs_find(0);
-  int sz = pLower->szOsFile;
+  unsigned int sz = pLower->szOsFile;
   memdb_vfs.pAppData = pLower;
   /* The following conditional can only be true when compiled for
   ** Windows x86 and SQLITE_MAX_MMAP_SIZE=0.  We always leave