(ITS#8453) lmdb: fix warning on Apple platforms

[catwell@archlinux.us]

Full_Name: Pierre Chapuis
Version: 
OS: macOS / iOS
URL: ftp://ftp.openldap.org/incoming/
Submission from: (NULL) (90.79.254.46)


Apple compilers (and probably others) do not allow calling sprintf with fewer
arguments than the format calls for.

The warning is:

    mdb.c:10720:46: warning: data argument not used by format string
[-Wformat-extra-args]
                                    (int)mr[i].mr_pid, (size_t)mr[i].mr_tid,
txnid);
                                   
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~
    /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS9.3.sdk/usr/include/secure/_stdio.h:47:56:
note:
          expanded from macro 'sprintf'
      __builtin___sprintf_chk (str, 0, __darwin_obsz(str), __VA_ARGS__)
                                                           ^~~~~~~~~~~


Proposed patch against current LMDB sterer:

    diff --git a/libraries/liblmdb/mdb.c b/libraries/liblmdb/mdb.c
    index 79a958b..84afe4f 100644
    --- a/libraries/liblmdb/mdb.c
    +++ b/libraries/liblmdb/mdb.c
    @@ -10715,9 +10715,13 @@ mdb_reader_list(MDB_env *env, MDB_msg_func *func,
void *ctx)
            for (i=0; i<rdrs; i++) {
                    if (mr[i].mr_pid) {
                            txnid_t txnid = mr[i].mr_txnid;
    -                       sprintf(buf, txnid == (txnid_t)-1 ?
    -                               "%10d %"Z"x -\n" : "%10d %"Z"x %"Y"u\n",
    -                               (int)mr[i].mr_pid, (size_t)mr[i].mr_tid,
txnid);
    +                       if (txnid == (txnid_t)-1) {
    +                               sprintf(buf, "%10d %"Z"x -\n",
    +                                       (int)mr[i].mr_pid,
(size_t)mr[i].mr_tid);
    +                       } else {
    +                               sprintf(buf, "%10d %"Z"x %"Z"u\n",
    +                                       (int)mr[i].mr_pid,
(size_t)mr[i].mr_tid, txnid);
    +                       }
                            if (first) {
                                    first = 0;
                                    rc = func("    pid     thread     txnid\n",
ctx);