Producing libname.so on AIX

    I've been debugging this long lasting PHP bug:
    
      http://bugs.php.net/bug.php?id=14245

    While doing this I encountered this part in the libtool.m4:

---cut---
    # Test if we are trying to use run time linking or normal
    # AIX style linking. If -brtl is somewhere in LDFLAGS, we
    # need to do runtime linking.
    case $host_os in aix4.[[23]]|aix4.[[23]].*|aix5*)
      for ld_flag in $LDFLAGS; do                        
        case $ld_flag in
          *-brtl*)
            aix_use_runtimelinking=yes
            break
            ;;     
         esac
      done
    esac
---cut---
    
    The problem is that 'case $host_os in aix4.[[23]]|aix4.[[23]].*|aix5*)' 
line.
    It doesn't seem to catch the "aix4.3.3.0" to which $host_os is set on
    the system I'm testing this on. (those double []'s perhaps?) 

    Setting LDFLAGS to have "-Wl,-brtl" does not have any effect.
    When I force 'aix_use_runtimelinking' to be always 'yes' in libtool.m4, 
    everything works fine.

    This bug (?) is still in the libtool.m4 from CVS HEAD too.
    
    --Jani