Wrong number of brakets in htonll test in configure.ac

When compile collectd in AIX htonll is defined, so the check in configure must work to detect this.

There is a problem with the brackets, in config.log:

    configure:18335: checking if have htonll defined
    configure:18359: /home/manuellsr/collectd-5.4.1/libltdl/config/compile gcc -o conftest -maix64 -D_THREAD_SAFE_ERRNO  -Wl,-brtl conftest.c  >&5
    conftest.c:139:1: error: expected identifier or '(' before '[' token
    conftest.c:145:1: error: expected identifier or '(' before ']' token
    configure:18359: $? = 1
    configure: failed program was:
    | /* confdefs.h */
    | #define PACKAGE_NAME "collectd"
    
    
    | #define HAVE_ONE_GETMNTENT 1
    | /* end confdefs.h.  */
    | [
    | #include <sys/types.h>
    | #include <netinet/in.h>
    | #if HAVE_INTTYPES_H
    | # include <inttypes.h>
    | #endif
    | ]
    | int
    | main ()
    | {
    | [
    |           return htonll(0);
    | ]
    |
    |   ;
    |   return 0;
    | }

Autoconf generate a pair of [ and ] in c check in configure:

    # Check for htonll
    { $as_echo "$as_me:${as_lineno-$LINENO}: checking if have htonll defined" >&5
    $as_echo_n "checking if have htonll defined... " >&6; }
        
        have_htonll="no"
        cat confdefs.h - <<_ACEOF >conftest.$ac_ext
    /* end confdefs.h.  */
    [ 
    #include <sys/types.h>
    #include <netinet/in.h>
    #if HAVE_INTTYPES_H
    # include <inttypes.h>
    #endif
    ]
    int
    main ()
    {
    [
              return htonll(0);
    ]   
    
      ;
      return 0;
    }