Change the xShmOpen() method of the VFS to take the database file name as

its argument, not the WAL file name.  Also fix some unrelated compiler
warnings.

FossilOrigin-Name: a65c2939267ef6acec4e355a207f98f217e263d6

src/mutex_noop.c

@@ -27,6 +27,7 @@
 */
 #include "sqliteInt.h"
 
+#ifndef SQLITE_MUTEX_OMIT
 
 #ifndef SQLITE_DEBUG
 /*
@@ -196,3 +197,4 @@ sqlite3_mutex_methods *sqlite3DefaultMutex(void){
   return sqliteNoopMutex();
 }
 #endif /* SQLITE_MUTEX_NOOP */
+#endif /* SQLITE_MUTEX_OMIT */