Merge all recent trunk enhancements into the sessions branch.

FossilOrigin-Name: 54aaa6f29ad1bf84148c2403eed77e8311f68d66

src/main.c

@@ -128,6 +128,11 @@ int sqlite3_initialize(void){
   }
 #endif
 
+  /* If the following assert() fails on some obscure processor/compiler
+  ** combination, the work-around is to set the correct pointer
+  ** size at compile-time using -DSQLITE_PTRSIZE=n compile-time option */
+  assert( SQLITE_PTRSIZE==sizeof(char*) );
+
   /* If SQLite is already completely initialized, then this call
   ** to sqlite3_initialize() should be a no-op.  But the initialization
   ** must be complete.  So isInit must not be set until the very end