Add the SQLITE_CONFIG_MMAP_LIMIT configuration option for overriding the

SQLITE_DEFAULT_MMAP_LIMIT compile-time setting.  Enhance "PRAGMA mmap_limit"
so that without a specific database name, it sets the limit on all database
files and changes the default for any future databases that might be added
using ATTACH.

FossilOrigin-Name: 78141d0a16dd1d56b575fccd149de7fa789cb06c

src/os_unix.c

@@ -3711,6 +3711,7 @@ static int unixFileControl(sqlite3_file *id, int op, void *pArg){
     }
     case SQLITE_FCNTL_MMAP_LIMIT: {
       pFile->mmapLimit = *(i64*)pArg;
+printf("MMAP-LIMIT(%s) -> %lld\n", pFile->zPath, pFile->mmapLimit);
       return SQLITE_OK;
     }
 #ifdef SQLITE_DEBUG